0.29.0 (2019-06-05)

Standard library

Fix example codes in multiple places. (#7718, thanks @maiha)

Macros

Fix inheritance support of record macro. (#7811, thanks @asterite)
Omit quotes in puts macro output. (#7734, thanks @asterite)

Numeric

(performance) Optimize String#to_u methods for the case of a negative number. (#7446, thanks @r00ster91)

Text

(breaking-change) Deprecate String#at, use String#char_at. (#7633, thanks @j8r)
(breaking-change) Change String#to_i to parse octals with prefix 0o (but not 0 by default). (#7691, thanks @icy-arctic-fox)
(breaking-change) Restrict some String#to_i arguments to be Bool. (#7436, thanks @j8r)
Add downcase option to String#camelcase. (#7717, thanks @wontruefree)
Add support for unicode 12.0.0. (#7721, thanks @Blacksmoke16)
Fix Unicode not showing up in the API docs. (#7720, thanks @r00ster91)

Collections

(breaking-change) Remove Slice#pointer. (#7581, thanks @Maroo-b)
Add sort methods to Slice. (#7597, thanks @Maroo-b)
Add Slice#[]?. (#7701, thanks @Sija)
Improve docs for Slice#[]. (#7780, thanks @Sija)

Serialization

YAML: let String handle numbers too. (#7809, thanks @asterite)

Time

Fix time format RFC 3339 to not include offset seconds. (#7492, thanks @straight-shoota)

Files

(breaking-change) Rename File::DEVNULL to File::NULL. (#7778, thanks @r00ster91)
Fix handling of files starting with ~ in Path#expand. (#7768, thanks @byroot)
Fix Dir.glob(match_hidden: false) not hiding hidden files properly. (#7774, thanks @ayazhafiz)

Networking

(breaking-change) Let IO#copy return UInt64. (#7660, thanks @asterite)
Add support for UDP multicast. (#7423, thanks @stakach)
Add missing requires to openssl.cr. (#7803, thanks @RX14)
Add IO::MultiWriter#flush. (#7765, thanks @mamantoha)
Add OpenSSL::SSL::Socket#cipher and #tls_version. (#7445, thanks @carlhoerberg)
Improve URI#normalize. (#7635, thanks @straight-shoota)
Improve documentation of some URI methods. (#7796, thanks @r00ster91)
Refactor StaticFileHandler specs for Last-Modified header. (#7640, thanks @straight-shoota)
Refactor compression usage in handler specs. (#7819, thanks @asterite)

Crypto

(breaking-change) Rename Crypto::Bcrypt::Password#== to #verify. (#7790, thanks @asterite)

Concurrency

Add docs for Channel. (#7673, thanks @j8r)

Compiler

(breaking-change) Fix require relative path resolution. (#7758, thanks @asterite)
(breaking-change) Disallow '!' or '?' at the end of the LHS in an assignment. (#7582, thanks @Maroo-b)
Allow running compiler_specs with specific flags. (#7837, thanks @bcardiff)
Fix extend from generic types. (#7812, thanks @asterite)
Don't virtualize types in Union(...) and keep more accurate type information. (#7815, thanks @asterite)
Do not generate debug metadata for arguments of naked functions. (#7775, thanks @eyusupov)
Detect deprecation on initialize methods and methods with named args. (#7724, thanks @bcardiff)
Fix track of AST nodes location. (#7827, thanks @asterite)
Fix offsetof not being usable with macros. (#7703, thanks @malte-v)
Allow parsing of call &.@ivar. (#7754, thanks @asterite)
Fix Def#to_s with **options and &block. (#7854, thanks @MakeNowJust)
Check pointerof inner expression for errors. (#7755, thanks @asterite)
Fix some error messages. (#7833, thanks @asterite)
Improve wording of pointerof(self) parser error. (#7542, thanks @r00ster91)
Fix typo. (#7828, thanks @RX14)

Language semantics

(breaking-change) Fix new/initialize lookup regarding modules. (#7818, thanks @asterite)
(breaking-change) Don't precompute sizeof on abstract structs and modules. (#7801, thanks @asterite)
Consider macro calls in @ivar initializer. (#7750, thanks @asterite)
Give precedence to T.class over Class in method lookup. (#7759, thanks @asterite)
Honor enum base type on non-default values. (#7776, thanks @asterite)
Avoid lookup of private def defined inside macro. (#7733, thanks @asterite)
Improve type flow of var in if with &&. (#7785, thanks @asterite)
Fix handling of NoReturn in if. (#7792, thanks @asterite)
Improve edge issues with while and rescue. (#7806, thanks @asterite)
Improve error on macro call in proc pointer. (#7757, thanks @asterite)
Fix error on named args forwarding. (#7756, thanks @asterite)
Check NoReturn type in named args. (#7761, thanks @asterite)
Fix internal handling of unbound/abstract generic types. (#7781, thanks @asterite)
Fix wrong cast to unbound generic type. (#7793, thanks @asterite)
Fix subclass observer to handle edge case call over generic types. (#7735, thanks @asterite)
Fix edge case of abstract struct with one subclass. (#7787, thanks @asterite)
Make automatic cast work with with ... yield. (#7746, thanks @asterite)

Tools

Allow to lookup class and module implementations. (#7742, thanks @MakeNowJust)
Refactor old duplicated 'def contains_target'. (#7739, thanks @MakeNowJust)

Formatter

Don't produce unnecessary newline before named args following heredoc. (#7695, thanks @MakeNowJust)
Fix formatting of multiline call arguments. (#7745, thanks @MakeNowJust)
Fix formatting of annotations with newlines and spaces. (#7744, thanks @MakeNowJust)
Refactor code to format &.[]. (#7699, thanks @MakeNowJust)

Others

CI improvements and housekeeping. (#7705, #7852, thanks @bcardiff)
Move VERSION inside ./src. (#7804, thanks @bcardiff)

0.28.0 (2019-04-17)

Language changes

(breaking-change) Enum declaration members can no longer be separated by a space, only by a newline, ; or ,, the latter being deprecated and reformatted to a newline. (#7607, #7618, thanks @asterite, and @j8r)
Add begin-less and end-less ranges: array[5..]. (#7179, thanks @asterite)
Add offsetof(Type, @ivar) expression. (#7589, thanks @malte-v)

Macros

Add Type#annotations to list all annotations and not just the last of each kind. (#7326, thanks @Blacksmoke16)
Add ArrayLiteral#sort_by macro method. (#3947, thanks @jreinert)

Standard library

(breaking-change) Allow creating None enum flag with Enum.from_value. (#6516, thanks @bew)
(breaking-change) Add deprecation message to PartialComparable. Its behaviour has been fully integrated into Comparable. (#7664, thanks @straight-shoota)
(performance) Optimize dwarf line numbers decoding. (#7413, thanks @asterite)
Fix Signal::CHLD.reset not clearing previous handler. (#7409, thanks @asterite)
Add lazy versions of Object.getter? and Object.property? macros. (#7322, thanks @Sija)
Allow returning other values than -1, 0 and 1 by Comparable#<=>. (#7277, thanks @r00ster91)
Add missing require statements to samples in the API docs. (#7564, thanks @Maroo-b)
Fix example codes in multiple places. (#7569, thanks @maiha)
Add documentation for @[Flags] and @[Link] annotations. (#7665, thanks @bcardiff)
Add documentation for Bool. (#7651, thanks @wontruefree)
Refactor to avoid usage of the thread-local $errno GLIBC_PRIVATE symbol. (#7496, thanks @felixvf)
Refactor to have similar signatures accross the stdlib for #to_s and #inspect. (#7528, thanks @wontruefree)

Numeric

(breaking-change) Add deprecation message to Int#/. It will return a Float in 0.29.0. Use Int#// for integer division. (#7639, thanks @bcardiff)
Change Number#inspect to not show the type suffixes. (#7525, thanks @asterite)
Add Int#leading_zeros_count and Int#trailing_zeros_count. (#7520, thanks @Sija)
Add Big*#//, BigInt#&-ops and missing #floor, #ceil, #trunc. (#7638, thanks @bcardiff)
Improve OverflowError message. (#7375, thanks @r00ster91)

Text

(performance) Optimize String#compare in case of ASCII only. (#7352, thanks @r00ster91)
Add methods for human-readable formatting of numbers: Number#format, Number#humanize, and Int#humanize_bytes. (#6314, thanks @straight-shoota)
Add String#rchop? and String#lchop?. (#7328, thanks @j8r)
Add options argument to String#camelcase and String#underscore. (#7374, thanks @r00ster91)
Add docs to Unicode::CaseOptions. (#7513, thanks @r00ster91)
Improve specs and docs for String#each_line and IO#each_line. (#7419, thanks @straight-shoota)

Collections

(breaking-change) Let Array#sort only use <=>, and let <=> return nil for partial comparability. (#6611, thanks @asterite)
(breaking-change) Drop Iterator#rewind. Implement #cycle by storing elements in an array. (#7440, thanks @asterite)
(performance) Add Enumerable#each_cons support for Deque as a reuse buffer. (#7233, thanks @yxhuvud)
(performance) Change Range#bsearch / 2 to >> 1 for faster performance. (#7531, thanks @Fryguy)
Fix Slice#clone for non-primitive types and deep copy. (#7591, thanks @straight-shoota)
Move Indexable#zip and Indexable#zip? to Enumerable and make it work with any number of Indexable or Iterable or Iterator. (#7453, thanks @asterite)
Add Slice#[](Range). (#7439, thanks @asterite)
Add nillable range fetching #[]?(Range) to Array and String. (#7338, thanks @j8r)
Add Set#add?. (#7495, thanks @Sija)
Improve documentation of Hash regarding ordering of items. (#7594, thanks @straight-shoota)

Serialization

(breaking-change) Change return type of YAML#libyaml_version to SemanticVersion. (#7555, thanks @asterite)
Fix support for libxml2 2.9.9. (#7477, thanks @asterite)
Fix support for libyaml 0.2.2. (#7555, thanks @asterite)
Add BigDecimal.from_yaml. (#7398, thanks @Sija)

Time

(breaking-change) Rename Time constructors. Deprecate Time.now to encourage usage Time.utc or Time.local (#5346, #7586, thanks @straight-shoota)
(breaking-change) Rename Time#add_span to Time#shift for changing a time instance by calendar units and handle other units. (#6598, thanks @straight-shoota)
(breaking-change) Change Time#date to return a Tuple of {year, month, day}. Use Time#at_beginning_of_day if a Time instance is wanted. (#5822, thanks @straight-shoota)
Fix Windows monotonic time bug. (#7377, thanks @domgetter)
Refactor Time methods. (#6581, thanks @straight-shoota)

Files

(breaking-change) Remove IO#flush_on_newline and only sync on STDOUT/STDIN/STDERR when they are TTY devices. (#7470, thanks @asterite)
Add Path type. (#5635, thanks @straight-shoota)

Networking

(breaking-change) Move HTTP::Multipart to MIME::Multipart. (#7085, thanks @m1lt0n)
(breaking-change) Stop parsing JSON in OAuth2 errors. (#7467, thanks @asterite)
(breaking-change) Fix RequestProcessor connection reuse logic. (#7055, thanks @straight-shoota)
(breaking-change) Replace HTTP.default_status_message_for(Int) with HTTP::Status.new(Int).description. (#7247, thanks @dwightwatson)
(breaking-change) Fix issues in URI implementation. URI#opaque method is merged into URI#path, which no longer returns Nil. #parse/#to_s normalization and default port handling has changed. (#6323, thanks @straight-shoota)
Fix write buffering in OpenSSL sockets. (#7460, thanks @carlhoerberg)
Fix leaks in HTTP::Server #bind_* and specs. (#7197, thanks @straight-shoota)
Add HTTP::Request#remote_address. (#7610, thanks @asterite)
Add HTTP::Status and Response#status. (#7247, #7682, thanks @dwightwatson, and @bcardiff)
Add support for OAuth 2.0 resource owner password credentials grant type. (#7424, thanks @Blacksmoke16)
Add support for IIS date format in cookies. (#7405, thanks @Sija)
Allow calls to IO::Syscall#wait_readable and IO::Syscall#wait_writable. (#7366, thanks @stakach)
Fix spec of HTTP::Client to not write server response after timeout. (#7402, thanks @asterite)
Fix spec of TCP::Server for musl. (#7484, thanks @straight-shoota)

Crypto

(breaking-change) Use OpenSSL::Algorithm instead of symbols for digest/hexdigest. Expose LibCrypt's PKCS5_PBKDF2_HMAC. (#7264, thanks @mniak)

Concurrency

Add multi-threading ready GC when compiling with -D preview_mt. (#7546, thanks @bcardiff, @waj, and @ysbaddaden)
Ship patched bdw-gc for multi-threading support. (#7622, thanks @bcardiff, and @ysbaddaden)
Refactor to extract Fiber::StackPool from Fiber. (#7417, thanks @ysbaddaden)
Refactor IO::Syscall as IO::Evented. (#7505, thanks @ysbaddaden)

System

Add command and args to execvp error message. (#7511, thanks @straight-shoota)
Refactor signals handling in a separate fiber. (#7469, thanks @asterite)

Spec

Improve how running specs are cancelled upon CTRL+C. (#7426, thanks @asterite)
Allow pending and it to accept constants. (#7646, thanks @straight-shoota)

Compiler

(performance) Avoid fork and spawn when --threads=1. (#7397, thanks @asterite)
Fix exception type thrown on missing require. (#7386, thanks @asterite)
Fix ICE when assigning a constant inside a multi-assign. (#7468, thanks @asterite)
Fix parsing and behaviour of ->foo.[] and other operators . (#7334, thanks @asterite)
Fix parsing bug in asm with 3 colons and a variable. (#7627, thanks @r00ster91)
Opt-in detection of calls to @[Deprecated] methods. (#7596, #7626, #7661, thanks @bcardiff)
Add CRYSTAL_LIBRARY_PATH for lookup static libraries. (#7562, thanks @bcardiff)
Improve error messages by adding the scope (and with ... yield scope, if any) on undefined method error. (#7384, thanks @asterite)
Suggest next when trying to break from captured block . (#7406, thanks @r00ster91)
Add detection of linux environment in compiler config. (#7479, thanks @straight-shoota)
Pending leftovers to support // and &-ops in multiple places. (#7628, thanks @bcardiff)
Refactor Crystal::Config.version to use read_file macro. (#7081, thanks @Sija)
Rewrite macro spec without executing a shell command. (#6962, thanks @asterite)
Fix typo in internals. (#7592, thanks @toshokan)

Language semantics

Fix issues with as, as? and unions and empty types. (#7475, thanks @asterite)
Fix method lookup when restrictions of instantiated and non-instantiated generic types are used. (#7537, thanks @bew)
Fix method lookup when free vars and explicit types are used. (#7536, #7580, thanks @bew)
When declaring a protected initialize, define a protected new. (#7510, thanks @asterite)
Fix named args type matching. (#7529, thanks @asterite)
Merge procs with the same arguments type and Nil | T return type to Nil return type. (#7527, thanks @asterite)
Fix passing recursive alias to proc. (#7568, thanks @asterite)

Tools

Suggest the user to run the formatter in travis.yml. (#7138, thanks @KCErb)

Formatter

Fix formatting of 1\n.as(Int32). (#7347, thanks @asterite)
Fix formatting of nested array elements. (#7450, thanks @MakeNowJust)
Fix formatting of comments and enums. (#7605, thanks @asterite)
Fix CLI handling of absolute paths input. (#7560, thanks @RX14)

Doc generator

Don't include private constants. (#7575, thanks @r00ster91)
Include Crystal built-in constants. (#7623, thanks @bcardiff)
Add compile-time flag to docs generator. (#6668, #7438, thanks @straight-shoota)
Display deprecated label when @[Deprecated] is used. (#7653, thanks @bcardiff)

Playground

Change the font-weight used for better readability. (#7552, thanks @Maroo-b)

Others

CI improvements and housekeeping. (#7359, #7381, #7388, #7387, #7390, #7622, thanks @bcardiff)
Smoke test linux 64 bits package using docker image recent build. (#7389, thanks @bcardiff)
Mention git pre-commit hook in CONTRIBUTING.md. (#7617, thanks @straight-shoota)
Fix misspellings throughout the codebase. (#7361, thanks @Sija)
Use chars instead of strings throughout the codebase. (#6237, thanks @r00ster91)
Fix GC finalization warning in Thread specs. (#7403, thanks @asterite)
Remove generated docs from linux packages. (#7519, thanks @straight-shoota)

0.27.2 (2019-02-05)

Standard library

Fixed integer overflow in main thread stack base detection. (#7373, thanks @ysbaddaden)

Networking

Fixes TLS exception during shutdown. (#7372, thanks @bcardiff)
Fixed HTTP::Client support exception on missing Content-Type. (#7371, thanks @bew)

0.27.1 (2019-01-30)

Language changes

Allow trailing commas inside tuple types. (#7182, thanks @asterite)

Standard library

(performance) Optimize generating UUID from String. (#7030, thanks @jgaskins)
(performance) Improve SemanticVersion operations. (#7234, thanks @j8r)
Fixed markdown inline code parsing. (#7090, thanks @MakeNowJust)
Fixed inappropriate uses of Time.now. (#7155, thanks @straight-shoota)
Make Nil#not_nil! raise NilAssertionError. (#7330, thanks @r00ster91)
Add SemanticVersion to API docs. (#7003, thanks @Blacksmoke16)
Add docs to discourage the use of Bool#to_unsafe other than for C bindings. (#7320, thanks @oprypin)
Refactor #to_s to be independent of the name method. (#7295, thanks @asterite)

Macros

Fixed docs of ArrayLiteral#unshift. (#7127, thanks @Blacksmoke16)
Fixed Annotation#[] to accept String and Symbol as keys. (#7153, thanks @MakeNowJust)
Fixed NamedTupleLiteral#[] to raise a compile error for invalid key type. (#7158, thanks @MakeNowJust)
Fixed getter/property macros to work properly with Bool types. (#7313, thanks @Sija)
Add read_file macro method. (#6967, #7094, thanks @Sija, @woodruffw)
Add StringLiteral#count. (#7239, thanks @Blacksmoke16)

Numeric

Fixed scale issues when dividing BigDecimal. (#7218, thanks @Sija)
Allow underscores in the String passed to Big* constructors. (#7107, thanks @Sija)
Add conversion methods and docs to Complex. (#5440, thanks @Sija)
Add specs for Int128, UInt128. (#7173, thanks @bcardiff)
Add unsafe number ops value.to_X!/T.new!/Int#&**. (#7226, thanks @bcardiff)
Add overflow detection with preview opt-in. (#7206, thanks @bcardiff)

Text

Fixed ECR location error reported. (#7137, thanks @MakeNowJust)
Add docs to ECR. (#7121, thanks @KCErb)
Refactor String#to_i to avoid future overflow. (#7172, thanks @bcardiff)

Collections

Fixed docs example in Hash#from. (#7210, thanks @r00ster91)
Fixed docs links of Enumerable#chunks and Iterator#chunk. (#6941, thanks @r00ster91)
Remove implicit null skip from Hash to JSON serialization. (#7053, thanks @MakeNowJust)
Add Iterator#slice_after. (#7146, thanks @asterite)
Add Iterator#slice_before. (#7152, thanks @asterite)
Add Iteratory#slice_when and Iterator#chunk_while. (#7159, thanks @asterite)
Add Enumerable#to_h(&block). (#7150, thanks @Sija)
Add Enumerable#one?. (#7166, thanks @asterite)
Add several Enumerable, Iterator and Array overloads that accept a pattern. (#7174, thanks @asterite)
Add docs to hash constructors. (#6923, thanks @KCErb)

Serialization

Add conversion between JSON and YAML. (#7232, thanks @straight-shoota)
Standardize #as_T/#as_T? methods between JSON::Any/YAML::Any. (#6556, thanks @j8r)
Add Set#from_yaml. (#6310, thanks @kostya)

Time

Fixed Time::Span initializer and sleep for big seconds. (#7221, thanks @asterite)
Fixed docs to show proper use of parse. (#7035, thanks @jwoertink)
Add missing Float#weeks method similar to Int#weeks. (#7165, thanks @vlazar)

Files

Fix mkstemps support on aarch64. (#7300, thanks @silmanduin66)
Validate LibC error codes in specs involving Errno errors. (#7087, thanks @straight-shoota)
Add microsecond precision to System::File.utime (Unix). (#7156, thanks @straight-shoota)
Add missing tempfile cleanup in specs. (#7250, thanks @bcardiff)
Add docs for file open modes. (#6664, thanks @r00ster91)

Networking

Fixed HTTP::Client edge case of exception during in TLS initialization. (#7123, thanks @asterite)
Fixed OpenSSL::SSL::Error.new to not raise Errno. (#7068, thanks @straight-shoota)
Fixed URI encoding in StaticFileHandler::DirectoryListing. (#7072, thanks @Sija)
Add MIME registry. (#5765, #7079, #7080, thanks @straight-shoota, @Sija)
Add MIME::MediaType for parsing mime media types. (#7077, thanks @straight-shoota)
Add support for 100-continue in HTTP::Server::Response. (#6912, thanks @jreinert)
Add support for creating sockets from raw file descriptors. (#6894, thanks @myfreeweb)
Add SNI support for OpenSSL. (#7291, thanks @bararchy)
Improve HTTP::Server docs. (#7251, thanks @straight-shoota)
Refactor OpenSSL specs to reduce chances of failing. (#7202, thanks @bcardiff)

Crypto

Add OpenSSL::Cipher#authenticated? to see if the cipher supports aead. (#7223, thanks @danielwestendorf)

System

Fixed inline ASM when compiling for ARM. (#7041, thanks @omarroth)
Implement Crystal::System for Win32. (#6972, thanks @markrjr)
Add Errno#errno_message getter. (#6702, thanks @r00ster91)

Spec

Detect nesting it and pending at run-time. (#7297, thanks @MakeNowJust)

Compiler

Fixed how LLVM::Type.const_int emit Int128 literals. (#7135, thanks @bcardiff)
Fixed ICE related to named tuples. (#7163, thanks @asterite)
Fixed automatic casting for private top-level methods. (#7310, thanks @asterite)
Give proper error if defining initialize inside enum, allow Enum.new. (#7266, thanks @asterite)
Give proper error when trying to access instance variable of union type. (#7194, thanks @asterite)
Give proper error when trying to instantiate Module. (#6735, thanks @r00ster91)
Give proper error related to named arguments. (#7288, thanks @asterite)
Parse required comma between block args. (#7343, thanks @asterite)
Improve inference in recursion that involves blocks. (#7161, thanks @asterite)
Add locations to all expanded macro arguments. (#7008, thanks @MakeNowJust)
Turn a not compiler specific error while requiring into ICE. (#7208, thanks @MakeNowJust)
Remove old nil? error on pointer types. (#7180, thanks @asterite)
Improve too big tuple and named tuple error message. (#7131, thanks @r00ster91)
Workaround buggy offset debug info values. (#7335, thanks @bcardiff)
Refactor extract helper methods to emit Float32, Float64 values. (#7134, thanks @bcardiff)
Refactor filename resolution logic out of interpret_run. (#7051, thanks @Sija)
Refactor internals regarding overflow. (#7262, thanks @bcardiff)
Refactor Crystal::Codegen::Target and consolidate triple handling. (#7282, #7317, thanks @RX14, @bcardiff)

Tools

Update README template. (#7118, thanks @mamantoha)
Capitalise Crystal in CLI output. (#7224, thanks @dwightwatson)

Formatter

Fixed formatting of multiline literal elements. (#7048, thanks @MakeNowJust)
Fixed formatting of heredoc with interpolations. (#7184, thanks @MakeNowJust)
Fixed prevent conflict between nested tuple types and macro expressions. (#7097, thanks @MakeNowJust)
Fixed format when typeof appears inside generic type. (#7176, thanks @asterite)
Fixed format of newline after &.foo in call. (#7240, thanks @MakeNowJust)
Honor same behaviour for single or multiple file arguments. (#7144, thanks @straight-shoota)
Refactor remove quotes from overflow symbols in formatter spec. (#6968, thanks @r00ster91)
Major rework of crystal tool format command. (#7257, thanks @MakeNowJust)

Doc generator

(security) Prevent XSS via args. (#7056, thanks @MakeNowJust)
Fixed generation of toplevel. (#7063, thanks @MakeNowJust)
Fixed display of double splat and block arg. (#7029, #7031, thanks @MakeNowJust)
Fixed keep trailing spaces in macros. (#7099, thanks @MakeNowJust)
Fixed avoid showing subtypes of aliased type. (#7124, thanks @asterite)
Fixed style of methods when hovering. (#7022, thanks @r00ster91)
Fixed duplicate source_link field. (#7033, thanks @bcardiff)
Fixed missing keywords in Doc::Highlighter. (#7054, thanks @MakeNowJust)
Add --format option to docs command. (#6982, thanks @mniak)

Others

CI improvements and housekeeping. (#7018, #7043, #7133, #7139, #7230, #7227, #7263, thanks @bcardiff)
CI split formatting check. (#7228, thanks @bcardiff)
Depend on standard variable to let the user define the build date. (#7186, thanks @eli-schwartz)
Reorganize community section in README, add forum. (#7235, thanks @straight-shoota)
Fixed docs grammar and typos. (#7034, #7242, #7331, thanks @r00ster91, @girng)
Improve samples. (#6454, thanks @r00ster91)
Fixed 0.27.0 CHANGELOG. (#7024, thanks @arcage)
Update ISSUE_TEMPLATE to include forum. (#7301, thanks @straight-shoota)
Update LICENSE's copyright year. (#7246, thanks @matiasgarciaisaia)

0.27.0 (2018-11-01)

Language changes

(breaking-change) Disallow comma after newline in argument list. (#6514, thanks @asterite)

Macros

Add Generic#resolve and Generic#resolve? macro methods. (#6617, thanks @asterite)

Standard library

Fixed v1, v2, v3, v4, v5 methods of UUID. (#6952, thanks @r00ster91)
Fixed multiple docs typos and phrasing in multiple places. (#6778, #6963, thanks @r00ster91)
Fixes Pointer/UInt subtraction. (#6994, thanks @damaxwell)
Add stack overflow detection. (#6928, #6995, thanks @damaxwell)
Add caller file and line to Nil#not_nil!. (#6712, thanks @yeeunmariakim)
Restrict Enum#parse/Enum#parse? to String arguments. (#6654, thanks @vladfaust)
Refactor and unify printing exceptions from within fibers. (#6594, thanks @Sija)
Improve docs on properties generated by property?. (#6682, thanks @epergo)
Add docs to top level namespace constants. (#6971, thanks @r00ster91)

Macros

Fix typos in StringLiteral#gsub and #tr errors. (#6925, thanks @r00ster91)

Numeric

(breaking-change) Disallow rand with zero value. (#6686, thanks @oprypin)
(breaking-change) Let == and != compare the values instead of bits when dealing with signed vs unsigned integers. (#6689, thanks @asterite)
Fixed Int#downto with unsigned int. (#6678, thanks @gmarcais)
Add wrapping arithmetics operators &+ &- &*. (#6890, thanks @bcardiff)
Add floor divisions operator Int#// and Float#//. (#6891, thanks @bcardiff)
Add random support for BigInt. (#6687, thanks @oprypin)
Add docs related to Float::Printer::*. (#5438, thanks @Sija)

Text

Add String::Builder#chomp! returns self. (#6583, thanks @Sija)
Add :default to colorize and document ColorRGB, Color256. (#6427, thanks @r00ster91)
Add String::Formatter support for c flag and improve docs. (#6758, thanks @r00ster91)

Collections

(breaking-change) Replace Indexable#at with #fetch. Remove Hash#fetch(key) as alias of Hash#[]. (#6296, thanks @AlexWayfer)
Add Hash/Indexable#dig/dig?. (#6719, thanks @Sija)
Add Iterator.chain to chain array of iterators. (#6570, thanks @xqyww123)
Add NamedTuple#to_h over empty tuples. (#6628, thanks @icyleaf)
Optimize Indexable#join when all elements are strings. (#6635, thanks @asterite)
Optimize Array#skip. (#6946, thanks @asterite)

Serialization

Fixed YAML::Schema::FailSafe.parse and parse_all. (#6790, thanks @r00ster91)
Fixed order of xmlns and prefix in XML::Builder#namespace. (#6743, thanks @yeeunmariakim)
Fixed CSV.build quoting of Char and Symbol. (#6904, thanks @maiha)
Fixed docs for JSON::Serializable. (#6950, thanks @Heaven31415)
Add XML::Attributes#delete. (#6910, thanks @joenas)
Add ability to quote values always in CSV.build. (#6723, thanks @maiha)
Refactor how empty properties are handled in JSON::Serializable and YAML::Serializable. (#6539, thanks @r00ster91)

Time

(breaking-change) Rename Time#epoch to Time#to_unix. Also #epoch_ms to #to_unix_ms, and #epoch_f to #to_unix_f. (#6662, thanks @straight-shoota)
Fixed spec for Time::Location.load_local with TZ=nil. (#6740, thanks @straight-shoota)
Add support for ISO calendar week to Time. (#6681, thanks @straight-shoota)
Add Time::Format support for %G, %g, %V. (#6681, thanks @straight-shoota)
Add Time::Location loader support for Windows. (#6363, thanks @straight-shoota)
Add Time#to_local_in to change time zone while keeping wall clock. (#6572, thanks @straight-shoota)
Add Time::UNIX_EPOCH and drop private UNIX_SECONDS constant. (#6908, thanks @j8r)
Change Time::DayOfWeek to ISO ordinal numbering based on Monday = 1. (#6555, thanks @straight-shoota)
Refactor time specs. (#6574, thanks @straight-shoota)
Add docs for singular method aliases, add Int#microsecond alias. (#6297, thanks @Sija)

Files

(breaking-change) Remove Tempfile. Use File.tempfile or File.tempname. (#6485, thanks @straight-shoota)
Fixed missing closed status check of FDs when creating a subprocess. (#6641, thanks @Timbus)
Fixed ChecksumReader.write error message. (#6889, thanks @r00ster91)
Add File#delete, Dir#tempdir and improve File docs. (#6485, thanks @straight-shoota)
Add File#fsync to flush all data written into the file to the disk device. (#6793, thanks @carlhoerberg)
Add DEVNULL to docs. (#6642, thanks @r00ster91)
Improve checks for FreeBSD version due to breaking API changes. (#6629, thanks @myfreeweb)
Improve performance of Zlib::Reader, Gzip::Reader and Flate::Reader by including IO::Buffered. (#6916, thanks @asterite)
Refactor Crystal::System::FileDescriptor to use @fd ivar directly. (#6703, thanks @straight-shoota)
Refactor {Zlib,Gzip,Flate}::Reader#unbuffered_rewind to use check_open. (#6958, thanks @Sija)

Networking

(breaking-change) Remove deprecated alias HTTP::Server#bind_ssl. Use HTTP::Server#bind_tls. (#6699, thanks @straight-shoota)
Add Socket::Address#pretty_print and #inspect. (#6704, thanks @straight-shoota)
Add Socket::IPAddress loopback, unspecified and broadcast methods/constants. (#6710, thanks @straight-shoota)
Fixed Socket#reuse_port? if SO_REUSEPORT is not supported. (#6706, thanks @straight-shoota)
Fixed TCPServer handling of reuse_port. (#6940, thanks @RX14)
Add docs to demonstrate parameters for HTTP::Client. (#5145, thanks @HCLarsen)
Add docs examples to Socket::Server#accept. (#6705, thanks @straight-shoota)
Refactor socket_spec.cr into separate files. (#6700, thanks @straight-shoota)
Refactor specs of HTTP::Client to remove inheritance for test server. (#6909, thanks @straight-shoota)
Improve specs for HTTP::Server#close. (#5958, thanks @straight-shoota)
Improve specs for socket. (#6711, thanks @straight-shoota)

Crypto

Fixed OpenSSL bindings to work with LibreSSL. (#6917, thanks @LVMBDV)
Add support for OpenSSL 1.1.1. (#6738, thanks @ysbaddaden)

Concurrency

Improve POSIX threads integration regarding locking, error and resource management. (#6944, thanks @ysbaddaden)
Remove unintended public methods from Channel. (#6714, thanks @asterite)
Refactor Fiber/Scheduler to isolate responsibilities. (#6897, thanks @ysbaddaden)
Refactor specs that relied on Fiber.yield behavior. (#6953, thanks @ysbaddaden)

System

Fixed fork and signal child handlers. (#6426, thanks @ysbaddaden)
Use blocking IO on a TTY if it can't be reopened. (#6660, thanks @Timbus)
Refactor Process in preparation for Windows support. (#6744, thanks @RX14)

Spec

Allow pending to be used without blocks. (#6732, thanks @tswicegood)
Add be_empty expectation. (#6614, thanks @mamantoha)
Add specs for expectation methods. (#6512, thanks @rodrigopinto)

Compiler

Fixed don't "ambiguous match" if there's an exact match. (#6618, thanks @asterite)
Fixed allow annotations inside enums. (#6713, thanks @asterite)
Fixed super inside macros will honor arguments. (#6638, thanks @asterite)
Fixed guessed ivar type from splat arguments. (#6648, thanks @MakeNowJust)
Fixed ASTNode#to_s of non-unary operator call without argument. (#6538, thanks @MakeNowJust)
Fixed ASTNode#to_s for multiline macro expression. (#6666, thanks @MakeNowJust)
Fixed ASTNode#to_s for {% verbatim do %} ... {% end %}. (#6665, thanks @MakeNowJust)
Fixed empty case statement normalization. (#6915, thanks @straight-shoota)
Fixed codegen of tuple elements with unreachable elements. (#6659, thanks @MakeNowJust)
Fixed parsing of // corner cases. (#6927, thanks @bcardiff)
Fixed recursive block expansion check for non ProcNotation restriction. (#6932, thanks @MakeNowJust)
Fixed corner case of expressions not typed on main phase but typed on cleanup phase. (#6720, thanks @MakeNowJust)
Improve error traces regarding return, next and break. (#6633, thanks @asterite)
Add resolve generics typenodes in macros. (#6617, thanks @asterite)
Add support for multiple output values in inline asm. (#6680, thanks @RX14)
Improve parsing of asm operands. (#6688, thanks @RX14)
Refactor rescue block codegen for Windows. (#6649, thanks @RX14)

Tools

Improve installation section in README template. (#6914, #6942, thanks @r00ster91)
Improve contributors section in README template. (#7005, thanks @r00ster91)

Formatter

Fixed formatting of {% verbatim do %} ... {% end %} outside macro. (#6667, thanks @MakeNowJust)
Fixed formatting of // corner cases. (#6927, thanks @bcardiff)
Improve formatting of asm operands. (#6688, thanks @RX14)

Doc generator

Add support for comments after :nodoc: marker. (#6627, thanks @Sija)
Fixed browser performance issue with blur filter. (#6764, thanks @girng)
Accessibility improvement in search field. (#6926, thanks @jodylecompte)

Others

CI improvements and housekeeping. (#6658, #6739, #6930, thanks @bcardiff, @RX14)
Add VERSION file and support for specifying the build commit. (#6966, thanks @bcardiff)
Add support for specifying the build date. (#6788, thanks @peterhoeg)
Update Contributing section in README.md. (#6911, thanks @r00ster91)

0.26.1 (2018-08-27)

Language changes

(breaking-change) Make self to be eager evaluated when including modules. (#6557, thanks @bcardiff)

Macros

Add accepts_block? macro method to Def. (#6604, thanks @willhbr)

Standard library

Macros

Fixed Object#def_hash can receive symbols. (#6531, thanks @Sija)

Collections

Add Hash#transform_keys and Hash#transform_values. (#4385, thanks @deepj)

Serialization

Fixed JSON::Serializable and YAML::Serializable clashing with custom initializers. (#6458, thanks @kostya)

Time

Fixed docs for Time::Format. (#6578, thanks @straight-shoota)

Files

Fixed zlib handling of buffer error. (#6610, thanks @asterite)

Networking

(deprecate) HTTP::Server#bind_ssl in favor of HTTP::Server#bind_tls. (#6551, thanks @bcardiff)
Add tls scheme to HTTP::Server#bind. (#6533, thanks @straight-shoota)
Fixed HTTP::Server crash with self-signed certificate. (#6590, thanks @bcardiff)
Refactor HTTP::Server specs to use free ports. (#6530, thanks @straight-shoota)

System

Improve STDIN/STDOUT/STDERR handling to avoid breaking other programs. (#6518, thanks @Timbus)

Spec

Fixed DotFormatter to flush after every spec. (#6562, thanks @asterite)
Add support for Windows. (#6497, thanks @RX14)

Compiler

Fixed evaluate yield expressions in macros. (#6587, thanks @asterite)
Fixed presence check of named argument via external name. (#6560, thanks @asterite)
Fixed parser error on break when. (#6509, thanks @asterite)
Fixed ~ methods are now able to be called as foo.~. (#6541, thanks @MakeNowJust)
Fixed parsing newline after macro control expression. (#6607, thanks @asterite)
Refactor use enum instead of hardcoded string values for emit kinds. (#6515, thanks @bew)

Tools

Formatter

Fixed formatting of newline before &.method in call. (#6535, thanks @MakeNowJust)
Fixed formatting of empty heredoc. (#6567, thanks @MakeNowJust)
Fixed formatting of string literal in interpolation. (#6568, thanks @MakeNowJust)
Fixed formatting of comments in case when. (#6595, thanks @asterite)

Doc generator

Add Menlo font family and fix ordering. (#6602, thanks @slice)

Playground

Fixed internal link. (#6596, thanks @omarroth)

Others

CI improvements and housekeeping. (#6550, #6612, thanks @bcardiff)
Add pkg-config as Linux package dependency. (distribution-scripts#16, thanks @bcardiff)

0.26.0 (2018-08-09)

Language changes

(breaking-change) Revert do not collapse unions for sibling types. (#6351, thanks @asterite)
(breaking-change) Constant lookup context in macro is now lexical. (#5354, thanks @MakeNowJust)
(breaking-change) Evaluate instance var initializers at the metaclass level (ie: disallow using self). (#6414, thanks @asterite)
(breaking-change) Add // operator parsing. NB: No behaviour is assigned to this operator yet. (#6470, thanks @bcardiff)
Add &+ &- &* &** operators parsing. NB: No behaviour is assigned to these operators yet. (#6329, thanks @bcardiff)
Add support for empty case without when. (#6367, thanks @straight-shoota)

Macros

Add pp! and p! macro methods. (#6374, #6476, thanks @straight-shoota)

Standard library

Fix docs for Pointer. (#6494, thanks @fxn)
Fix docs of UUID enums. (#6496, thanks @r00ster91)

Numeric

Fixed Random#rand(Range(Float, Float)) to return Float. (#6445, thanks @straight-shoota)
Add docs of big module overloads. (#6336, thanks @laginha87)

Text

(breaking-change) String#from_utf16(pointer : Pointer(UInt16)) returns now {String, Pointer(UInt16)}. (#6333, thanks @straight-shoota)
Add support for unicode 11.0.0. (#6505, thanks @asterite)
Add an optional argument to String#check_no_null_byte to customize error message. (#6333, thanks @straight-shoota)
Add ECR.render for rendering directly as String. (#6371, thanks @straight-shoota)
Fix docs for Char (#6487, thanks @r00ster91)

Collections

Add docs for StaticArray. (#6404, #6488, thanks @straight-shoota, @r00ster91, @hinrik)
Refactor Array#concat. (#6493, thanks @fxn)

Serialization

(breaking-change) Add a maximum nesting level to prevent stack overflow on YAML::Builder and JSON::Builder. (#6322, thanks @asterite)
Fixed compatibility for libyaml 0.2.1 regarding document end marker .... (#6287, thanks @straight-shoota)
Add methods and options for pull parsing or hybrid parsing to XML::Reader. (#5740, #6332, thanks @felixbuenemann)
Fixed docs for JSON::Any, JSON::Serialization and YAML::Serialization. (#6460, #6491, thanks @delef, @bmulvihill)

Time

(breaking-change) Make location a required argument for Time.parse. (#6369, thanks @straight-shoota)
Add Time.parse!, Time.parse_utc, Time.parse_local. (#6369, thanks @straight-shoota)
Fix docs comment missing (#6387, thanks @faustinoaq)

Files

(breaking-change) Remove File.each_line method that returns an iterator. Use IO#each_line. (#6301, thanks @asterite)
Fixed File.join when path separator is a component argument. (#6328, thanks @icyleaf)
Fixed Dir.glob can now list broken symlinks. (#6466, thanks @straight-shoota)
Add File and Dir support for Windows. (#5623, thanks @RX14)

Networking

(breaking-change) Drop HTTP::Server#tls in favor of HTTP::Server#bind_ssl. (#5960, thanks @straight-shoota)
(breaking-change) Rename alias HTTP::Handler::Proc to HTTP::Handler::HandlerProc. (#6453, thanks @jwoertink)
Fixed Socket#accept? base implementation. (#6277, thanks @ysbaddaden)
Fixed performance issue due to unbuffered IO read. IO#sync only affect writes, introduce IO#read_buffering?. (#6304, #6474, thanks @asterite, @bcardiff)
Fixed handling of closed state in HTTP::Server::Response. (#6477, thanks @straight-shoota)
Fixed change encoding name comparison to be case insensitive for UTF-8. (#6355, thanks @asterite)
Fixed support for quoted charset value in HTTP. (#6354, thanks @asterite)
Fixed docs regarding udp example on Socket::Addrinfo. (#6388, thanks @faustinoaq)
Fixed HTTP::Client will set connection: close header on one-shot requests. (#6410, thanks @asterite)
Fixed OpenSSL::Digest for multibyte strings. (#6471, thanks @RX14)
Fixed missing Host header when using HTTP::Client#exec. (#6481, thanks @straight-shoota)
Add HTTP::Server#bind(URI|String) that infers protocol from scheme. (#6500, thanks @straight-shoota)
Add HTTP::Params.new and HTTP::Params#empty?. (#6241, thanks @icyleaf)
Add support for multiple Etags in If-None-Match header for HTTP::Request and HTTP::StaticFileHandler. (#6219, thanks @straight-shoota)
Add IDNs normalization to punycode in OpenSSL::SSL::Socket. (#6306, thanks @paulkass)
Add application/wasm to the default MIME types of HTTP::StaticFileHandler. (#6377, thanks @MakeNowJust)
Add URI#absolute? and URI#relative?. (#6311, thanks @mamantoha)

Crypto

Fixed Crypto::Bcrypt::Password#== was hiding Reference#==(other). (#6356, thanks @straight-shoota)

Concurrency

Fixed Atomic#swap with reference types. (#6428, thanks @Exilor)

System

Fixed raise Errno if Process.new fails to exec. (#6501, thanks @straight-shoota, @lbguilherme)
Add support for WinError UTF-16 string messages. (#6442, thanks @straight-shoota)
Refactor platform specifics from ENV to Crystal::System::Env and implement for Windows. (#6333, #6499, thanks @straight-shoota)

Spec

Add TAP formatter to spec suite. (#6286, thanks @straight-shoota)

Compiler

Fixed named arguments expansion from double splat clash with local variable names. (#6378, thanks @asterite)
Fixed auto assigned ivars arguments expansions when clash with keywords. (#6379, thanks @asterite)
Fixed resulting type of union of tuple metaclasses. (#6342, thanks @asterite)
Fixed ICE when using unbound type parameter inside generic type. (#6292, thanks @asterite)
Fixed ICE when using unions of metaclasses. (#6307, thanks @asterite)
Fixed ICE related to literal type guessing and generic types hierarchy. (#6341, thanks @asterite)
Fixed ICE related to not and inlinable values. (#6452, thanks @asterite)
Fixed rebind variables type in while condition after analyzing its body. (#6295, thanks @asterite)
Fixed corner cases regarding automatic casts and method instantiation. (#6284, thanks @asterite)
Fixed parsing of \A (and others) inside %r{...} inside macros. (#6282, thanks @asterite)
Fixed parsing of of named tuple inside generic type arguments. (#6413, thanks @asterite)
Fixed disallow cast from module class to virtual metaclass. (#6320, thanks @asterite)
Fixed disallow return inside a constant's value. (#6347, thanks @asterite)
Fixed debug info for closured self. (#6346, thanks @asterite)
Fixed parsing error of newline before closing macro. (#6382, thanks @asterite)
Fixed missing error if constant has NoReturn type. (#6411, thanks @asterite)
Fixed give proper error when doing sizeof uninstantiated generic type. (#6418, thanks @asterite)
Fixed private aliases at top-level are now considered private. (#6432, thanks @asterite)
Fixed setters with multiple arguments as now disallowed. (#6324, thanks @maxfierke)
Fixed type var that resolves to number in restriction didn't work. (#6504, thanks @asterite)
Add support for class variables in generic classes. (#6348, thanks @asterite)
Add support for exception handling in Windows (SEH). (#6419, thanks @RX14)
Refactor codegen of binary operators. (#6330, thanks @bcardiff)
Refactor use JSON::Serializable instead of JSON.mapping. (#6308, thanks @kostya)
Refactor Crystal::Call#check_visibility and extract type methods. (#6484, thanks @asterite, @bcardiff)
Change how metaclasses are shown. Use Foo.class instead of Foo:Class. (#6439, thanks @RX14)

Tools

Flatten project structure created by crystal init. (#6317, thanks @straight-shoota)

Formatter

Fixed formatting of { {1}.foo, ...} like expressions. (#6300, thanks @asterite)
Fixed formatting of when with numbers. Use right alignment only if all are number literals. (#6392, thanks @MakeNowJust)
Fixed formatting of comment in case's else. (#6393, thanks @MakeNowJust)
Fixed code fence when language is not crystal will not be formatted. (#6424, thanks @asterite)

Doc generator

Add line numbers at link when there are duplicated filenames in "Defined in:" section. (#6280, #6489, thanks @r00ster91)
Fix docs navigator not scrolling into open type on page load. (#6420, thanks @soanvig)

Others

Fixed system_spec does no longer emit errors messages on BSD platforms. (#6289, thanks @jcs)
Fixed compilation issue when running spec against compiler and std together. (#6312, thanks @straight-shoota)
Add support for LLVM 6.0. (#6381, #6380, #6383, thanks @felixbuenemann)
CI improvements and housekeeping. (#6313, #6337, #6407, #6408, #6315, thanks @bcardiff, @MakeNowJust, @r00ster91, @maiha)

0.25.1 (2018-06-27)

Standard library

Macros

Fixed Object.delegate is now able to be used with []= methods. (#6178, thanks @straight-shoota)
Fixed p! pp! are now able to be used with tuples. (#6244, thanks @bcardiff)
Add #copy_with method to structs generated by record macro. (#5736, thanks @chris-baynes)
Add docs for ArrayLiteral#push and #unshift. (#6232, thanks @MakeNowJust)

Collections

Add docs for Indexable#zip and #zip? methods. (#5734, thanks @rodrigopinto)

Serialization

Add #dup and #clone for JSON::Any and YAML::Any. (6266, thanks @asterite)
Add docs example of nesting mappings to YAML.builder. (#6097, thanks @kalinon)

Time

Fixed docs regarding formatting and parsing Time. (#6208, #6214, thanks @r00ster91 and @straight-shoota)
Fixed Time internals for future Windows support. (#6181, thanks @RX14)
Add Time::Span#microseconds, Int#microseconds and Float#microseconds. (#6272, thanks @asterite)
Add specs. (#6174, thanks @straight-shoota)

Files

Fixed File.extname edge case. (#6234, thanks @bcardiff)
Fixed FileInfo#flags return value. (#6248, thanks @fgimian)

Networking

Fixed IO#write(slice : Bytes) won't write information if slice is empty. (#6269, thanks @asterite)
Fixed docs regarding HTTP::Server#bind_tcp method. (#6179, #6233, thanks @straight-shoota and @MakeNowJust)
Add Etag support in HTTP::StaticFileHandler. (#6145, thanks @emq)

Misc

Fixed mmap usage on OpenBSD 6.3+. (#6250, thanks @jcs)
Fixed big/big_int, big/big_float, etc are now able to be included directly. (#6267, thanks @asterite)
Refactor dependency in Crystal::Hasher to avoid load order issues. (#6184, thanks @ysbaddaden)

Compiler

Fixed a leakage of unbounded generic type variable and show error. (#6128, thanks @asterite)
Fixed error message when lookup of library fails and lib's name contains non-alpha chars. (#6187, thanks @oprypin)
Fixed integer kind deduction for very large negative numbers. (#6182, thanks @rGradeStd)
Refactor specs tempfiles and data files usage in favor of portability (#5951, thanks @straight-shoota)
Improve formatting and information in some compiler error messages. (#6261, thanks @RX14)

Tools

Formatter

Fixed crash when semicolon after block paren were present. (#6192, thanks @MakeNowJust)
Fixed invalid code produced when heredoc and comma were present. (#6222, thanks @straight-shoota and @MakeNowJust)
Fixed crash when one-liner begin/rescue were present. (#6274, thanks @asterite)

Doc generator

Fixed JSON export that prevent jumping to constant. (#6218, thanks @straight-shoota)
Fixed crash when virtual types were reached. (#6246, thanks @bcardiff)

Misc

CI improvements and housekeeping. (#6193, #6211, #6209, #6221, #6260, thanks @bcardiff, @kostya and @r00ster91)
Update man page. (#6259, thanks @docelic)

0.25.0 (2018-06-11)

New features and breaking changes

(breaking-change) Time zones has been added to Time. (#5324, #5819, thanks @straight-shoota)
(breaking-change) Drop HTTP.rfc1123_date in favor of HTTP.format_time and add time format implementations for ISO-8601, RFC-3339, and RFC-2822. (#5123, thanks @straight-shoota)
(breaking-change) crystal deps is removed, use shards. (#5544, thanks @asterite)
(breaking-change) Hash#key was renamed as Hash#key_for. (#5444, thanks @marksiemers)
(breaking-change) JSON::Any and YAML::Any have been re-implemented solving some inconsistencies and avoiding the usage of recursive aliases (JSON::Type and YAML::Type have been removed). (#5183, thanks @asterite)
(breaking-change) Multiple heredocs can be used as arguments and methods can be invoked writing them in the initial delimiter, also empty heredocs are now supported. (#5578, #5602, #6048, thanks @asterite and @MakeNowJust)
(breaking-change) Refactor signal handlers and avoid closing pipe at exit. (#5730, thanks @ysbaddaden)
(breaking-change) Improve behaviour of File.join with empty path component. (#5915, thanks @straight-shoota)
(breaking-change) Drop Colorize#push in favor of Colorize#surround and allow nested calls across the stack. (#4196, thanks @MakeNowJust)
(breaking-change) File.stat was renamed to File.info and a more portable API was implemented. (#5584, #6161, thanks @RX14 and @bcardiff)
(breaking-change) Refactor HTTP::Server to bind to multiple addresses. (#5776, #5959, thanks @straight-shoota)
(breaking-change) Remove block argument from loop. (#6026, thanks @asterite)
(breaking-change) Do not collapse unions for sibling types. (#6024, thanks @asterite)
(breaking-change) Disallow typeof in type restrictions. (#5192, thanks @asterite)
(breaking-change) Perform unbuffered read when IO::Buffered#sync = true. (#5849, thanks @RX14)
(breaking-change) Drop when _ support. (#6150, thanks @MakeNowJust)
(breaking-change) The DivisionByZero exception was renamed to DivisionByZeroError. (#5395, thanks @sdogruyol)
A bootstrap Windows port has been added to the standard library. It's not usable for real programs yet. (#5339, #5484, #5448, thanks @RX14)
Add automatic casts on literals arguments for numbers and enums. (#6074, thanks @asterite)
Add user defined annotations. (#6063, #6084, #6106, thanks @asterite)
Add macro verbatim blocks to avoid nested macros. (#6108, thanks @asterite)
Allow namespaced expressions to define constants eg: Foo::Bar = 1. (#5883, thanks @bew)
Allow trailing = in symbol literals. (#5969, thanks @straight-shoota)
Allow redefining None to 0 for @[Flags] enum. (#6160, thanks @bew)
Suggest possible solutions to failing requires. (#5487, thanks @RX14)
Allow pointers of external C library global variables. (#4845, thanks @larubujo)
Decouple pretty-printing (pp) and showing the expression (!): p, pp, p!, pp!. (#6044, thanks @asterite)
Add ivars default value reflection in macros. (#5974, thanks @asterite)
Add argless overload to Number#round to rounds to the nearest whole number. (#5397, thanks @Sija)
Add Int#bits_set? to easily check that certain bits are set. (#5619, thanks @RX14)
Add Float32 and Float64 constants. (#4787, thanks @konovod)
Add allocated bytes per operation in Benchmark.ips. (#5522, thanks @asterite)
Add String#to_utf16 and String.from_utf16. (#5541, #5579, #5583 thanks @asterite, @RX14 and @straight-shoota)
Add String#starts_with?(re: Regex). (#5485, thanks @MakeNowJust)
Add Regex.needs_escape?. (#5962, thanks @Sija)
Add Hash#last_key and Hash#last_value. (#5760, thanks @j8r)
Add no-copy iteration to Indexable. (#4584, thanks @cjgajard)
Add Time#at_{beginning,end}_of_second (#6167, thanks @straight-shoota)
Add IO::Stapled to combine two unidirectional IOs into a single bidirectional one. (#6017, thanks @straight-shoota)
Add context to errors in JSON.mapping generated code. (#5932, thanks @straight-shoota)
Add JSON::Serializable and YAML::Serializable attribute powered mappings. (#6082, thanks @kostya)
Add mode param to File.write. (#5754, thanks @woodruffw)
Add Punycode/IDNA support and integrate with DNS lookup. (#2543, thanks @MakeNowJust)
Add HTTP::Client#options method. (#5824, thanks @mamantoha)
Add support for Last-Modified and other cache improvements to HTTP::StaticFileHandler. (#2470, #5607, thanks @bebac and @straight-shoota)
Add operations and improvements related to BigDecimal and BigFloat. (#5437, #5390, #5589, #5582, #5638, #5675, thanks @Sija and @mjago)
Add BigDecimal and UUID JSON support. (#5525, #5551, thanks @lukeasrodgers and @lachlan)
Add missing UUID#inspect. (#5574, thanks @ngsankha)
Add Logger configuration in initializer. (#5618, thanks @Sija)
Add custom separators in CSV.build. (#5998, #6008 thanks @Sija)
Add INI.build to emit INI files. (#5298, thanks @j8r)
Add Process.chroot. (#5577, thanks @chris-huxtable)
Add Tempfile.tempname to create likely nonexisting filenames. (#5360, thanks @woodruffw)
Add FileUtils#ln, ln_s, and ln_sf. (#5421, thanks @woodruffw)
Add support 8bit and true color to Colorize. (#5902, thanks @MakeNowJust)
Add comparison operators between classes. (#5645, thanks @asterite)
Add exception cause in backtrace. (#5833, thanks @RX14)
Add unhandled exception as argument in at_exit. (#5906, thanks @MakeNowJust)
Add support to target aarch64-linux-musl. (#5861, thanks @jirutka)
Add #clear method to ArrayLiteral/HashLiteral for macros. (#5265, thanks @Sija)
Add Bool#to_unsafe for C bindings. (#5465, thanks @woodruffw)
Spec: Add expectations starts_with, ends_with. (#5881, thanks @kostya)
Formatter: Add --include and --exclude options to restrict directories. (#4635, thanks @straight-shoota)
Documentation generator: improved navigation, searching, rendering and SEO. (#5229, #5795, #5990, #5657, #6073, thanks @straight-shoota, @Sija and @j8r)
Playground: Add button in playground to run formatter. (#3652, thanks @samueleaton)

Standard library bugs fixed

Fixed String#sub handling of negative indexes. (#5491, thanks @MakeNowJust)
Fixed String#gsub in non-ascii strings. (#5350, thanks @straight-shoota)
Fixed String#dump for UTF-8 characters higher than \uFFFF. (#5668, thanks @straight-shoota)
Fixed String#tr edge case optimization bug. (#5913, thanks @MakeNowJust)
Fixed String#rindex when called with Regex. (#5594, thanks @straight-shoota)
Fixed Time::Span precision loss and boundary check. (#5563, #5786, thanks @petoem and @straight-shoota)
Array#sample was fixed to use the provided random number generator (instead of the default) in all cases. (#5419, thanks @c910335)
Add short-circuit logic in Deque#rotate! for singleton and empty queues. (#5399, thanks @willcosgrove)
Slice#reverse! was optimised to be up to 43% faster. (#5401, thanks @larubujo)
Fixed Regex#inspect when escaping was needed. (#5841, thanks @MakeNowJust)
Fixed JSON.mapping now generates type restriction on getters. (#5935, thanks @Daniel-Worrall)
Fixed JSON.mapping documentation regarding unions. (#5483, thanks @RX14)
Fixed JSON.mapping and YAML.mapping to allow properties property. (#5180, #5352, thanks @maxpowa and @Sija)
Fixed YAML int and float parsing. (#5699, #5774, thanks @straight-shoota)
Fixed WebSocket handshake validation. (#5327, #6027 thanks @straight-shoota)
Fixed HTTP::Client is able to use ipv6 addresses. (#6147, thanks @bcardiff)
Fixed handling some invalid responses in HTTP::Client. (#5630, thanks @straight-shoota)
Fixed HTTP::ChunkedContent will raise on unterminated content. (#5928, #5943, thanks @straight-shoota)
URI#to_s now handles default ports for lots of schemes. (#5233, thanks @lachlan)
HTTP::Cookies is able to deal with spaces in cookies. (#5408, thanks @bararchy)
Fixed MIME type of SVG images in HTTP::StaticFileHandler. (#5605, thanks @damianham)
Fixed URI encoding in StaticFileHandler#redirect_to. (#5628, thanks @straight-shoota)
Fixed before_request callbacks to be executed right before writing the request in HTTP::Client. (#5626, thanks @asterite)
Dir.glob was re-implemented with performance improvements and edge cases fixed. (#5179, thanks @straight-shoota)
Fixed File.extname edge case for '.' in path with no extension. (#5790, thanks @codyjb)
Some ECDHE curves were incorrectly disabled in OpenSSL clients, this has been fixed. (#5494, thanks @jhass)
Fixed allow bcrypt passwords up to 71 bytes. (#5356, thanks @ysbaddaden)
Unhandled exceptions occurring inside Process.fork now print their backtrace correctly. (#5431, thanks @RX14)
Fixed Zip no longer modifies deflate signature. (#5376, thanks @luislavena)
Fixed INI parser edge cases and performance improvements. (#5442, #5718 thanks @woodruffw, @j8r)
Fixed initialization of LibXML. (#5587, thanks @lbguilherme)
Some finalizers were missing for example when the object where cloned. (#5367, thanks @alexbatalov)
Fixed sigfault handler initialization regarding sa_mask. (#5677 thanks @ysbaddaden)
Fixed missing reference symbol in ARM. (#5640, thanks @blankoworld)
Fixed detect LLVM 5.0 by llvm-config-5.0 command. (#5531, thanks @Vexatos)
Restore STDIN|OUT|ERR blocking state on exit. (#5802, thanks @bew)
Fixed multiple at_exit handlers chaining. (#5413, thanks @bew)
Fixed senders were not notified when channels were closed. (#5880, thanks @carlhoerberg)
Fixed forward unhandled exception to caller in parallel macro. (#5726, thanks @lipanski)
Fixed Markdown parsing of code fences appearing on the same line. (#5606, thanks @oprypin)
Fixed OpenSSL bindings to recognize LibreSSL. (#5676, #6062, #5949, #5973 thanks @LVMBDV and @RX14)
Fixed path value in to UNIXSocket created by UNIXServer. (#5869, thanks @straight-shoota)
Fixed Object.delegate over setters. (#5964, thanks @straight-shoota)
Fixed pp will now use the same width on every line. (#5978, thanks @MakeNowJust)
Fixes missing stdarg.cr for i686-linux-musl. (#6120, thanks @bcardiff)
Spec: Fixed junit spec formatter to emit the correct XML. (#5463, thanks @hanneskaeufler)

Compiler bugs fixed

Fixed enum generated values when a member has value 0. (#5954, thanks @bew)
Fixed compiler issue when previous compilation was interrupted. (#5585, thanks @asterite)
Fixed compiler error with an empty ensure block. (#5396, thanks @MakeNowJust)
Fixed parsing regex in default arguments. (#5481, thanks @MakeNowJust)
Fixed parsing error of regex literal after open parenthesis. (#5453, thanks @MakeNowJust)
Fixed parsing of empty array with blank. (#6107, thanks @asterite)
Static libraries are now found correctly when using the --static compiler flag. (#5385, thanks @jreinert)
Improve error messages for unterminated literals. (#5409, thanks @straight-shoota)
Fixed ProcNotation and ProcLiteral introspection in macros. (#5206, thanks @javanut13)
Cross compilation honors --emit and avoid generating bc_flags in current directory. (#5521, thanks @asterite)
Fixed compiler error with integer constants as generic arguments. (#5532, thanks @asterite)
Fixed compiler error with self as base class. (#5534, thanks @asterite)
Fixed macro expansion when mutating the argument. (#5247, thanks @MakeNowJust)
Fixed macro expansion edge cases. (#5680, #5842, #6163, thanks @asterite, @MakeNowJust and @splattael)
Fixed macro overload on named args. (#5808, thanks @bew)
Fixed macro numeric types used in interpreter. (#5972, thanks @straight-shoota)
Fixed missing debug locations in several places. (#5597, thanks @asterite)
Fixed missing information in AST nodes needed for macro expansion. (#5454, thanks @MakeNowJust)
Fixed multiline error messages in emitted by ASTNode#raise macro method. (#5670, thanks @asterite)
Fixed nested delimiters and escaped whitespace in string/symbol array literals. (#5667, thanks @straight-shoota)
Fixed custom array/hash-like literals in nested modules. (#5685, thanks @asterite)
Fixed usage of static array in C externs. (#5690, thanks @asterite)
Fixed spawn over expression with receivers. (#5781, thanks @straight-shoota)
Fixed prevent heredoc inside interpolation. (#5648, thanks @MakeNowJust)
Fixed parsing error when a newline follows block arg. (#5737, thanks @bew)
Fixed parsing error when macro argument is followed by a newline. (#6046, thanks @asterite)
Fixed compiler error messages wording. (#5887, thanks @r00ster91)
Fixed recursion issues in method_added macro hook. (#5159, thanks @MakeNowJust)
Fixed avoid using type of updated argument for type inference. (#5166, thanks @MakeNowJust)
Fixed parsing error message on unbalanced end brace in macros. (#5420, thanks @MakeNowJust)
Fixed parsing error message on keywords are used as arguments. (#5930, #6052, thanks @MakeNowJust and @esse)
Fixed parsing error message on missing comma for named tuples. (#5981, thanks @MakeNowJust)
Fixed missing handling of cond node in visitor. (#6032, thanks @veelenga)
Fixed cli when --threads has invalid value. (#6039, thanks @r00ster91)
Fixed private methods can now be called with explicit self receiver. (#6075, thanks @MakeNowJust)
Fixed missing some missing rules of initializer in initializers macro methods. (#6077, thanks @asterite)
Fixed regression bug related to unreachable code. (#6045, thanks @asterite)

Tools bugs fixed

Several crystal init and template improvements. (#5475, #5355, #4691, #5788, #5644, #6031 thanks @woodruffw, @faustinoaq, @bew, @kostya and @MakeNowJust)
Formatter: improve formatting of method call arguments with trailing comments. (#5492, thanks @MakeNowJust)
Formatter: fix formatting of multiline statements. (#5234, #5901, #6013 thanks @MakeNowJust)
Formatter: fix formatting of multi assignment. (#5452, thanks @MakeNowJust)
Formatter: fix formatting of backslash ending statements. (#5194, thanks @asterite)
Formatter: fix formatting of .[] methods. (#5424, thanks @MakeNowJust)
Formatter: fix formatting of statements with comments. (#5655, #5893, #5909, thanks @MakeNowJust)
Formatter: fix formatting of nested begin/end. (#5922, thanks @MakeNowJust)
Formatter: fix formatting of trailing comma with block calls. (#5855, thanks @MakeNowJust)
Formatter: fix formatting of ending expression after heredoc. (#6127, thanks @asterite)
Documentation generator: references to nested types in markdown are now correctly parsed. (#5308, thanks @straight-shoota)
Documentation generator: fix leftovers regarding default old doc directory. (#5406, thanks @GloverDonovan)
Documentation generator: avoid failing on non git directory. (#3700, thanks @MakeNowJust)
Crystal::Doc::Highlighter has specs now (#5368, thanks @MakeNowJust)
Playground: can now be run with HTTPS. (#5527, thanks @opiation)
Playground: Pretty-print objects in inspector. (#4601, thanks @jgaskins)

Misc

The platform-specific parts of File and IO::FileDescriptor were moved to Crystal::System, as part of preparation for the Windows port. (#5333, #5553, #5622 thanks @RX14)
The platform-specific parts of Dir were moved to Crystal::System, as part of preparation for the Windows port. (#5447, thanks @RX14)
Incremental contributions regaring Windows support. (#5422, #5524, #5533, #5538, #5539, #5580, #5947 thanks @RX14 and @straight-shoota)
The build on OpenBSD was fixed. (#5387, thanks @wmoxam)
Add support for FreeBSD 12 (64-bit inodes). (#5199, thanks @myfreeweb)
Scripts and makefiles now depend on sh instead of bash for greater portability. (#5468, thanks @j8r)
Honor LDFLAGS and EXTRA_FLAGS in Makefile. (#5423, #5860, thanks @trofi, @jirutka)
Improve message on link failure. (#5486, #5603, thanks @RX14 and @waj)
Improve String#to_json when chars don't need escaping. (#5456, thanks @larubujo)
Improve Time#add_span when arguments are zero. (#5787, thanks @straight-shoota)
Improve String#pretty_print to output by splitting newline. (#5750, thanks @MakeNowJust)
Add \a escape sequence. (#5864, thanks @r00ster91)
Several miscellaneous minor code cleanups and refactors. (#5499, #5502, #5507, #5516, #4915, #5526, #5529, #5535, #5537, #5540, #5435, #5520, #5530, #5547, #5543, #5561, #5599, #5493, #5546, #5624, #5701, #5733, #5646, #5729, #5791, #5859, #5882, #5899, #5918, #5896, #5810, #5575, #5785, #5866, #5816, #5945, #5963, #5968, #5977, #6004, #5794, #5858, #6033, #6036, #6079, #6111, #6118, #6141, #6142, #5380, #6071, thanks @chastell, @lachlan, @bew, @RX14, @sdogruyol, @MakeNowJust, @Sija, @noriyotcp, @asterite, @splattael, @straight-shoota, @r00ster91, @jirutka, @paulcsmith, @rab, @esse, @carlhoerberg, @chris-huxtable, @luislavena)
Several documentation fixes and additions. (#5425, #5682, #5779, #5576, #5806, #5817, #5873, #5878, #5637, #5885, #5884, #5728, #5917, #5912, #5894, #5933, #5809, #5936, #5908, #5851, #5378, #5914, #5967, #5993, #3482, #5946, #6095, #6117, #6131, #6162, thanks @MakeNowJust, @straight-shoota, @vendethiel, @bew, @Heaven31415, @marksiemers, @Willamin, @r00ster91, @maiha, @Givralix, @docelic, @CaDs, @esse, @igneus, @masukomi)
CI housekeeping and including 32 bits automated builds. (#5796, #5804, #5837, #6015, #6165, thanks @bcardiff, @bew and @Sija)
Sync docs in master to https://crystal-lang.org/api/master. (#5941, thanks @bcardiff)
Enable the large heap configuration for libgc. (#5839, thanks @RX14)
Improve Ctrl-C handling of spec. (#5719, thanks @MakeNowJust)
Playground: Update to codemirror 5.38.0. (#6166, thanks @bcardiff)

0.24.2 (2018-03-08)

Fixed an Index out of bounds raised during at_exit (#5224, #5565, thanks @ysbaddaden)
Re-add Dir#each so it complies with Enumerable (#5458, thanks @bcardiff)
Fixed SSL::Context bug verifying certificates (#5266, #5601, thanks @waj)
Fixed UUID documentation that was missing (#5478, #5542, thanks @asterite)
Fixed a bug with single expressions in parenthesis (#5482, #5511, #5513, thanks @MakeNowJust)
Fixed skip_file macro docs (#5488, thanks @straight-shoota)
Fixed CI build script's LIBRARY_PATH (#5457, #5461, thanks @bcardiff)
Fixed formatter bug with upper-cased fun names (#5432, #5434, thanks @bew)

0.24.1 (2017-12-23)

New features

Add ThinLTO support for faster release builds in LLVM 4.0 and above. (#4367, thanks @bcardiff)
(breaking-change) Add UUID type. Random::Secure.uuid has been replaced with UUID.random. (#4453, thanks @wontruefree)
Add a BigDecimal class for arbitrary precision, exact, decimal numbers. (#4876 and #5255, thanks @vegai and @Sija)
Allow Set to work as a case condition, which matches when the case variable is inside the set. (#5269, thanks @MakeNowJust)
(breaking-change) Change Time::Format codes to allow more robust options for parsing sub-second precision times. (#5317, thanks @bcardiff)
Add Time.utc, an alias of Time.new which shortens creating UTC times. (#5321, thanks @straight-shoota)
Add custom extension support to Tempfile. (#5264, thanks @jreinert)
Add reduce method to TupleLiteral and ArrayLiteral when using macros. (#5294, thanks @javanut13)
Export a JSON representation of the documentation in the generated output. (#4746 and #5228, thanks @straight-shoota)
Make gc/none garbage collection compile again and allow it to be enbled using -Dgc_none compiler flag. (#5314, thanks @ysbaddaden)

Standard library bugs fixed

Make String#[] unable to read out-of-bounds when the string ends in a unicode character. (#5257, thanks @Papierkorb)
Fix incorrect parsing of long JSON floating point values. (#5323, thanks @benoist)
Replace the default hash function with one resistant to hash DoS. (#5146, thanks @funny-falcon)
Ensure equal numbers always have the same hashcode. (#5276, thanks @akzhan)
Fix struct equality when two structs descend from the same abstract struct. (#5254, thanks @hinrik)
Fix URI#full_path not to append a ? unless the query params are nonempty. (#5340, thanks @paulcsmith)
Fix HTTP::Params.parse to parse && correctly. (#5274, thanks @akiicat)
Disallow null bytes in ENV keys and values. (#5216, thanks @Papierkorb)
Disallow null bytes in XML::Node names and content. (#5200, thanks @RX14)
Fix IO#blocking= on OpenBSD. (#5283, thanks @wmoxam)
Fix linking programs in OpenBSD. (#5282, thanks @wmoxam)

Compiler bugs fixed

Stop incorrectly finding top-level methods when searching for a super method. (#5202, thanks @lbguilherme)
Fix parsing regex literals starting with a ; directly after a call (ex p /;/). (#5208, thanks @MakeNowJust)
Correct a case where Expressions#to_s could produce invalid output, causing macro expansion to fail. (#5226, thanks @asterite)
Give error instead of crashing when self is used at the top level. (#5227, thanks @MakeNowJust)
Give error instead of crashing when using instance_sizeof on a generic type without providing it's type arguments. (#5209, thanks @lbguilherme)
Fix parsing calls when short block syntax (&.foo) is followed by a newline. (#5237, thanks @MakeNowJust)
Give error instead of crashing when an unterminated string array literal (%w()) sits at the end of a file. (#5241, thanks @asterite)
Give error when attempting to use macro yield ({{yield}}) outside a macro. (#5307, thanks @MakeNowJust)
Fix error related to generic inheritance. (#5284, thanks @MakeNowJust)
Fix compiler crash when using recursive alias and generics. (#5330, thanks @MakeNowJust)
Fix parsing foo(+1) as foo + 1 instead of foo(1) where foo was a local variable. (#5336, thanks @MakeNowJust)
Documentation generator: Keep quoted symbol literals quoted when syntax highlighting code blocks in documentation output. (#5238, thanks @MakeNowJust)
Documentation generator: Keep the original delimiter used when syntax highlighting string array literals. (#5297, thanks @MakeNowJust)
Documentation generator: Fix XSS vulnerability when syntax highlighting string array literals. (#5259, thanks @MakeNowJust)
Formatter: fix indentation of the last comment in a begin/end block. (#5198, thanks @MakeNowJust)
Formatter: fix formatting parentheses with multiple lines in. (#5268, thanks @MakeNowJust)
Formatter: fix formatting $1?. (#5313, thanks @MakeNowJust)
Formatter: ensure to insert a space between { and % characters to avoid forming {% macros. (#5278, thanks @MakeNowJust)

Misc

Fix Makefile, CI, and gitignore to use the new documentation path after #4937. (#5217, thanks @straight-shoota)
Miscellaneous code cleanups. (#5318, #5341 and #5366, thanks @bew and @mig-hub)
Documentation fixes. (#5253, #5296, #5300 and #5322, thanks @arcage, @icyleaf, @straight-shoota and @bew)
Fix the in-repository changelog to include 0.24.0. (#5331, thanks @sdogruyol)

0.24.0 (2017-10-30)

(breaking-change) HTTP::Client#post_form is now HTTP::Client.post(form: ...)
(breaking-change) Array#reject!, Array#compact! and Array#select! now return self (#5154)
(breaking-change) Remove the possibility to require big_int, big_float or big_rational individually: use require "big" instead (#5121)
(breaking-change) Spec: remove expect_raises without type argument (#5096)
(breaking-change) IO is now a class, no longer a module (#4901)
(breaking-change) Time constructors now have nanosecond and kind as named argument (#5072)
(breaking-change) Removed XML.escape. Use HTML.escape instead (#5046)
(breaking-change) Removed macro def (#5040)
(breaking-change) SecureRandom is now Random::Secure (#4894)
(breaking-change) HTML.escape now only escapes &<>"' (#5012)
(breaking-change) To define a custom hash method you must now define hash(hasher) (#4946)
(breaking-change) Flate::Reader.new(&block) and Flate::Writer.new(&block) now use the name open (#4887)
(breaking-change) Use an Enum for Process stdio redirections (#4445)
(breaking-change) Remove '$0' special syntax
(breaking-change) Remove bare array creation from multi assign (a = 1, 2, 3) (#4824)
(breaking-change) Rename skip macro method to skip_file (#4709)
(breaking-change) StaticArray#map and Slice#map now return their same type instead of Array (#5124)
(breaking-change) Tuple#map_with_index now returns a Tuple. (#5086)
Packages built with LLVM 3.9.1. They should (hopefully) fix #4719
Syntax: Allow flat rescue/ensure/else block in do/end block (#5114)
Syntax: fun names and lib function calls can now start with Uppercase
Macros: Using an alias in macros will now automatically resolve it to is aliased type (#4995)
Macros: The flags bits32 and bits64 are now automatically defined in macros
The YAML module has now full support for the 1.1 core schema with additional types, and properly supports aliases and merge keys (#5007)
Add --output option to crystal docs (#4937)
Add Time#days_in_year: it returns the no of days in a given year (#5163)
Add Time.monotonic to return monotonic clock (#5108)
Add remove_empty option to many String#split overloads
Add Math.sqrt overloads for Bigs (#5113)
Add --stdin-filename to crystal command to compile source from STDIN (#4571)
Add Crystal.main to more easily redefine the main of a program (#4998)
Add Tuple.types that returns a tuple of types (#4962)
Add NamedTuple.types that returns a named tuple of types (#4962)
Add NamedTuple#merge(other : NamedTuple) (#4688)
Add YAML and JSON.mapping presence: true option (#4843)
Add Dir.each_child(&block) (#4811)
Add Dir.children (#4808)
HTML.unescape now supports all HTML5 named entities (#5064)
Regex now supports duplicated named captures (#5061)
rand(0) is now valid and returns 0
Tuple#[] now supports a negative index (#4735)
JSON::Builder#field now accepts non-scalar values (#4706)
Number#inspect now shows the number type
Some additions to Big arithmetics (#4653)
Increase the precision of Time and Time::Span to nanoseconds (#5022)
Upgrade Unicode to 10.0.0 (#5122)
Support LLVM 5.0 (#4821)
Lots of bugs fixed

0.23.1 (2017-07-01)

Added Random::PCG32 generator (See #4536, thanks @konovod)
WebSocket should compare "Upgrade" header value with case insensitive (See #4617, thanks @MakeNowJust)
Fixed macro lookup from included module (See #4639, thanks @asterite)
Explained "crystal tool expand" in crystal(1) man page (See #4643, thanks @MakeNowJust)
Explained how to detect end of file in IO (See #4661, thanks @oprypin)

0.23.0 (2017-06-27)

(breaking-change) Logger#formatter takes a Severity instead of a String (See #4355, #4369, thanks @Sija)
(breaking-change) Removed IO.select (See #4392, thanks @RX14)
Added Crystal::System::Random namespace (See #4450, thanks @ysbaddaden)
Added Path#resolve? macro method (See #4370, #4408, thanks @RX14)
Added range methods to BitArray (See #4397, #3968, thanks @RX14)
Added some well-known HTTP Status messages (See #4419, thanks @akzhan)
Added compiler progress indicator (See #4182, thanks @RX14)
Added System.cpu_cores (See #4449, #4226, thanks @miketheman)
Added separator and quote_char to CSV#each_row (See #4448, thanks @timsu)
Added map_with_index! to Pointer, Array and StaticArray (See #4456, #3356, #3354, thanks @Nephos)
Added headers parameter to HTTP::WebSocket constructors (See #4227, #4222, thanks @adamtrilling)
Added unlink to XML::Node (See #4515, #4331, thanks @RX14 and @MrSorcus)
Added Math.frexp (See #4560, thanks @akzhan)
Added Regex::MatchData support for negative indexes (See #4566, thanks @MakeNowJust)
Added captures, named_captures, to_a and to_h to Regex::MatchData (See #3783, thanks @MakeNowJust)
Added | as a string delimiter to allow q|string| syntax (See #3467, thanks @RX14)
Added support for Windows linker (See #4491, thanks @RX14)
Added llvm operand bundle def and catch pad/ret/switch in order to support Windows SEH (See #4501, thanks @bcardiff)
Added Float::Printer based on Grisu3 to speed up float to string conversion (See #4333, thanks @will)
Added Object.unsafe_as to unsafely reinterpret the bytes of an object as being of another type (See #4333, thanks @asterite)
Added .downcase(Unicode::CaseOptions::Fold) option which convert strings to casefolded strings for caseless matching (See #4512, thanks @akzhan)
Added OpenSSL::DigestIO to wrap an IO while calculating a digest (See #4260, thanks @spalladino)
Added zero? to numbers and time spans (See #4026, thanks @jellymann)
Added TypeNode#has_method? method (See #4474, thanks @Sija)
Regex::MatchData#size renamed to #group_size (See #4565, thanks @MakeNowJust)
HTTP::StaticFileHandler can disable directory listing (See #4403, #4398, thanks @joaodiogocosta)
bin/crystal now uses /bin/sh instead of /bin/bash (See #3809, #4410, thanks @TheLonelyGhost)
crystal init generates a .editorconfig file (See #4422, #297, thanks @akzhan)
man page for crystal command (See #2989, #1291, thanks @dread-uo)
Re-raising an exception doesn't overwrite its callstack (See #4487, #4482, thanks @akzhan)
MD5 and SHA1 documentation clearly states they are not cryptographically secure anymore (See #4426, thanks @RX14)
Documentation about constructor methods now rendered separately (See #4216, thanks @Sija)
Turn Random::System into a module (See #4542, thanks @oprypin)
Regex::MatchData pretty printed (See #4574, thanks @MakeNowJust)
String.underscore treats digits as downcase or upcase characters depending previous characters (See #4280, thanks @MakeNowJust)
Refactor time platform specific implementation (See #4502, thanks @bcardiff)
Fixed Crystal not reusing .o files across builds (See #4336)
Fixed SomeClass.class.is_a?(SomeConst) causing an "already had enclosing call" exception (See #4364, #4390, thanks @rockwyc992)
Fixed HTTP::Params.parse query string with two = gave wrong result (See #4388, #4389, thanks @akiicat)
Fixed Class.class.is_a?(Class.class.class.class.class) 🎉 (See #4375, #4374, thanks @rockwyc992)
Fixed select hanging when sending before receive (See #3862, #3899, thanks @kostya)
Fixed "Unknown key in access token json: id_token" error in OAuth2 client (See #4437)
Fixed macro lookup conflicting with method lookup when including on top level (See #236)
Fixed Vagrant images (See #4510, #4508, thanks @Val)
Fixed IO::FileDescriptor#seek from current position (See #4558, thanks @ysbaddaden)
Fixed IO::Memory#gets_to_end to consume the IO (See #4415, thanks @jhass)
Fixed setting of XML attributes (See #4562, thanks @asterite)
Fixed "SSL_shutdown: Operation now in progress" error by retrying (See #3168, thanks @akzhan)
Fixed WebSocket negotiation (See #4386, thanks @RX14)

0.22.0 (2017-04-20)

(breaking-change) Removed Process.new(pid) is now private (See #4197)
(breaking-change) IO#peek now returns an empty slice on EOF (See #4240, #4261)
(breaking-change) Rename WeakRef#target to WeakRef#value (See #4293)
(breaking-change) Rename HTTP::Params.from_hash to HTTP::Params.encode (See #4205)
(breaking-change) '\"' is now invalid, use '"' (See #4309)
Improved backtrace function names are now read from DWARF sections (See #3958, thanks @ysbaddaden)
Improved sigfaults and exceptions are printed to STDERR (See #4163, thanks @Sija)
Improved SSL Sockets are now buffered (See #4248)
Improved type inference on loops (See #4242, #4243)
Improved pp and p, the printed value is returned (See #4285, #4283, thanks @MakeNowJust)
Added support for OpenSSL 1.1.0 (See #4215, #4230, thanks @ysbaddaden)
Added SecureRandom#random_bytes(Bytes) (See #4191, thanks @konovod)
Added setting and deleting of attributes on XML::Node (See #3902, thanks @bmmcginty)
Added File.touch and FileUtils.touch methods (See #4069, thanks @Sija)
Added #values_at for CSV (See #4157, thanks @need47)
Added Time#clone (See #4174, thanks @Sija)
Added ancestors macro method (See #3875, thanks @david50407)
Added skip macro method (#4237, thanks @mverzilli)
Added Colorize.on_tty_only! for easier toggling (See #4075, #4271, thanks @MakeNowJust)
Added WebSocket#on_binary to receive binary messages (See #2774, thanks @lbguilherme)
Fixed Iterator.of stops iterating when Iterator.stop is returned (See #4208)
Fixed String#insert for non-ascii Char (See #4164, thanks @Papierkorb)
Fixed File.link now creates a hard link (#4116, thanks @KCreate)
Fixed error message for #to_h over empty NamedTuple (See #4076, thanks @karlseguin)
Fixed NamedTuple#to_h does no longer call to value's #clone (See #4203)
Fixed Math#gamma and Math#lgamma (See #4229, thanks @KCreate)
Fixed TCPSocket creation for 0 port for Mac OSX (See #4177, thanks @will)
Fixed repo name extraction from git remote in doc tool (See #4132, thanks @Sija)
Fixed self resolution when including a generic module (See #3972, thanks @MakeNowJust)
Fixed debug information was missing in some cases (See #4166, #4202, #4254)
Fixed use generic ARM architecture target triple for all ARM architectures (See #4167, thanks @ysbaddaden)
Fixed macro run arguments escaping
Fixed zsh completion (See #4284, thanks @veelenga)
Fixed honor --no-color option in spec (See #4306, thanks @luislavena)
Some bug fixes

0.21.1 (2017-03-06)

Improved lookup of abstract def implementors (see #4052)
Improved allocation of objects without pointer instance variables using malloc_atomic (see #4081)
Added crystal --version reports also the LLVM version (see #4095, thanks @matiasgarciaisaia)
Fixed instance variables initializers corner cases (see #3988)
Fixed crystal play was broken (see #4061)
Fixed Atomic can be set to nil (see #4062)
Fixed GZip::Header extra byte (see #4068, thanks @crisward)
Fixed ASTNode#to_s for Attribute (see #4098, thanks @olbat)
Some bug fixes

0.21.0 (2017-02-20)

(breaking-change) The compiler now reuses previous macro run compilations so {{ run(...) }} is only re-run if the code changes
(breaking-change) Spec: assert { ... } is now it { ... } (thanks @TheLonelyGhost)
(breaking-change) Renamed Set#merge! to Set#concat
(breaking-change) Zlib was split into Flate, Gzip and Zlib (bda40f)
(breaking-change) Crypto::MD5 is now Digest::MD5
(breaking-change) String#chop is now String#rchop
(breaking-change) String#to_slice now returns a read-only Slice
(breaking-change) String can now hold invalid UTF-8 byte sequences, and they produce a unicode replacement character when traversed
(breaking-change) Removed String#lchomp. Use String#lchop
(breaking-change) Octal escapes inside strings incorrectly produced a codepoint value instead of a byte value
(breaking-change) Removed octal escape from char literals
Fixed compiler performance regression related to cached files (f69e37e)
Added \xHH escape sequence in string literals
Char::Reader can now traverse a string backwards
Enum#to_s now uses pipes instead of commas for flag enums
IO#read_string is now encoding-aware
OAuth2::Client now sends application/json Accept header, and considers the expires_in access token property as optional
Slice can now be read-only
TCPServer no longer set SO_REUSEPORT to true by default
Added HTTP::Multipart and HTTP::FormData (thanks @RX14)
Added File::Stat#pipe?
Added File.utime
Added IO#peek
Added String#strip(arg), String#lstrip(arg), String#rstrip(arg)
Added String#lchop, String#lchop(prefix), String#rchop and String#rchop(suffix)
Added String#hexbytes and String#hexbytes?
Added String#scrub and String#valid_encoding?
Added include? macro method for StringLiteral, SymbolLiteral and MacroId (thanks @karlseguin)
Added "view source" links to GitLab (thanks @ezrast)
Updated CONTRIBUTING.md guidelines
Some bug fixes

0.20.5 (2017-01-20)

Improved performance in String#index, String#rindex due to Rabin-Karp algorithm (thanks @MakeNowJust).
Improved performance in Crypto::Bcrypt (see #3880, thanks @ysbaddaden).
expect_raises returns raised exception (thanks @kostya).
Line numbers debug information is always generated (see #3831, thanks @ysbaddaden).
Added Zip::File, Zip::Reader and Zip::Writer. Native readers for zip files that delegate compression to existing zlib module.
Added Hash#delete with block (see #3856, thanks @bmulvihill).
Added String#[](char : Char) (see #3855, thanks @Sija).
Added crystal tool expand to expand macro call in a given location (see #3732, thanks @MakeNowJust).
Fixed crystal play is able to show compilation errors again.
crystal doc recognizes crystal-lang/crystal in any remote (thanks @MaxLap).
Some bug fixes

0.20.4 (2017-01-06)

(breaking change) A type that wants to convert itself to JSON now must override to_json(builder : JSON::Builder) instead of to_json(io : IO). The same is true for custom JSON converters. If you are using JSON.mapping then your code will continue to work without changes.
(breaking change) Defining a finalize method on a struct now gives a compile error
(breaking change) Default argument types now must match their restriction, if any (for example def foo(x : Int32 = nil) will now fail to compile if foo is invoked without arguments) (thanks @MakeNowJust)
(breaking change) each methods now return Nil
(breaking change) IO#skip(bytes) will now raise if there aren't at least the given amount of bytes in the IO (previously it would work well if there were less bytes, and it would hang if there were more)
(breaking change) MemoryIO was removed (use IO::Memory instead)
(breaking change) Number#step now requires named arguments, to and by, to avoid argument order confusion
(breaking change) YAML::Emitter was renamed to YAML::Builder, and some of its methods were also renamed
(breaking change) XML::Node#[] now always returns a String (previously it could also return Nil, which was incorrect)
(breaking change) XML::Node#content now returns an empty String when no content is available
HTTP::Client now automatically reconnects on a dropped keep-alive connection
with ... yield now works well with method_missing
Class variables can now be used in generic types (all generic instances share the same variable, and subclasses get their own copy, as usual)
Added support for LLVM 4 (thanks @ysbaddaden)
Added Enum.each and Enum#each (thanks @ysbaddaden)
Added Hash#compact and Hash#compact! (thanks @MakeNowJust)
Added IO#read_string(bytesize)
Added IO#skip_to_end
Added Iterator#flat_map (thanks @MakeNowJust)
Added JSON.build and JSON::Builder
Added NamedTuple#has_key?(String) (thanks @Sija)
Added p(NamedTuple) (thanks @splattael)
Added Regex::MatchData#== (thanks @MakeNowJust)
Added String#sub(Regex, NamedTuple) (thanks @maiha)
Added XML.build and XML::Builder
Lots of improvements and applied consistencies to doc comments (thanks @Sija and @maiha)
Some bug fixes

0.20.3 (2016-12-23)

(breaking change) IO#gets, IO#each_line, String#lines, String#each_line, etc. now chomp lines by default. You can pass chomp: false to prevent automatic chomping. Note that chomp is true by default for argless IO#gets (read line) but false if args are given.
(breaking change) HTTP::Handler is now a module instead of a class (thanks @andrewhamon)
(breaking change) Free variables now must be specified with forall, a single uppercase letter will not work anymore
(breaking change) The libs directory is no longer in the default CRYSTAL_PATH, use lib (running crystal deps should fix this)
Optimized compile times, specially on linux
private can now be used with macros inside types (thanks @MakeNowJust)
CLI: the -s/--stats option now also shows execution time (thanks @MakeNowJust)
CLI: added -t/--time to show execution time (thanks @MakeNowJust)
Socket now allows any family/type/protocol association, and many other improvements (thanks @ysbaddaden)
YAML: an IO can now be passed to from_yaml (thanks @MakeNowJust)
Added class_getter, class_setter, class_property, etc. (thanks @Sija)
Added String#lchomp (thanks @Sija)
Added IO#read_fully?
Added Iterator#flatten (thanks @MakeNowJust)
Added HTTP::WebSocket#ping, pong, on_ping, on_pong, and now a ping message is automatically replied with a pong message (thanks @Sija)
Added File#empty? and Dir#empty? (thanks @dylandrop)
Added Time::Span#/(Time::Span) (thanks @RX14)
Added String#split versions that accept a block (thanks @splattael)
Added URI#normalize and normalize! (thanks @taylorfinnell)
Added reuse optional argument to many Array, Enumerable and Iterable methods that allow you to reuse the yielded/return array for better performance and less memory footprint
The :debug flag is now present when compiled with --debug, useful for doing flag?(:debug) in macros (thanks @luislavena)
Many bug fixes and performance improvements

0.20.1 (2016-12-05)

(breaking change) Set#merge as renamed to Set#merge!
(breaking change) Slice.new(size) no longer works with non primitive integers and floats
(breaking change) The macro method argify was renamed to splat
Added pretty printing. The methods p and pp now use it. To get the old behaviour use puts obj.inspect
Added ArrayLiteral#[]=, TypeNode#constant, TypeNode#overrides? and HashLiteral#double_splat in macros
Added a finished macro hook that runs at the end of the program
Added support for declaring the type of a local variable
Added Slice.empty
Flags enums now have a none? method
IO::ByteFormat has now methods to encode/decode to/from a Slice
Spec: the line number passed to run a specific it block can now be inside any line of that block
The CallConvention attribute can now also be applied to a lib declaration, and all funs inside it will inherit it
The method_missing hook can now define a method, useful for specifying block arguments
Support double splat in macros ({{**...}})
Some bug fixes

0.20.0 (2016-11-22)

(breaking change) Removed ifdef from the language
(breaking change) Removed PointerIO
(breaking change) The body property of HTTP::Request is now an IO? (previously it was String). Use request.body.try(&.gets_to_end) if you need the entire body as a String.
(breaking change) MemoryIO has been renamed to IO::Memory. The old name can still be used but will produce a compile-time warning. MemoryIO will be removed immediately after 0.20.0.
(breaking change) Char#digit? was split into Char#ascii_number? and Char#number?. The old name is still available and will produce a compile-time warning, but will be removed immediately after 0.20.0.
(breaking change) Char#alpha? was split into Char#ascii_letter? and Char#letter?. The old name is still available and will produce a compile-time warning, but will be removed immediately after 0.20.0.
(breaking change) The Iterable module is now generic
Many String and Char methods are now unicode-aware, for example String#downcase, String#upcase, Char#downcase, Char#upcase, Char#whitespace?, etc.
Added support for HTTP client and server streaming.
Added support for ARM (thanks @ysbaddaden)
Added support for AArch64 (thanks @ysbaddaden)
Added support for LLVM 3.9 (thanks @ysbaddaden)
Added __END_LINE__ magic constant in method default arguments: will be the last line of a call (if the call has a block, it will be the last line of that block)
Added @def inside macros that takes the value of the current method
API docs have a nicer style now, and notes like TODO and DEPRECATED are better highlighted (thanks @samueleaton)
Slight improvement to debugging support (thanks @ggiraldez)
Line numbers in backtraces (linux only for now) (thanks @ysbaddaden)
Added iteration times to Benchmark.ips (thanks @RX14)
Allow HTTP::Client block initializer to be used when passing an URI (thanks @philnash)
JSON.mapping and YAML.mapping getter/setter generation can now be controlled (thanks @zatherz)
Time is now serializable to JSON and YAML using ISO 8601 date-time format
Added IO::MultiWriter (thanks @RX14)
Added String#index(Regex) and String#rindex(Regex) (thanks @zatherz)
Added String#partition and String#rpartition (thanks @johnjansen)
Added FileUtils.cd, FileUtils.mkdir, FileUtils.mkdir_p, FileUtils.mv, FileUtils.pwd, FileUtils.rm, FileUtils.rm_r, FileUtils.rmdir (thanks @ghivert)
Added JSON::Builder#raw_field (thanks @kostya)
Added Enumerable#chunks and Iterator#chunk (thanks @kostya)
Added Iterator#with_index
Several enhancements to the Random module: now works for any integer type and avoids overflows (thanks @BlaXpirit)
Optimized Array#sort by using introsort (thanks @c910335)
Several bug fixes

0.19.4 (2016-10-07)

Added support for OpenBSD (thanks @wmoxam and @ysbaddaden)
More iconv fixes for FreeBSD (thanks @ysbaddaden)
Changed how require works for the upcoming shards release (this is backwards compatible). See crystal-lang#2788
Added Atomic and exposed all LLVM atomic instructions to Crystal (needed to implemented multiple-thread support)
Added Process.executable_path (thanks @kostya, @whereami and @ysbaddaden)
Added HTML.unescape (thanks @dukex)
Added Char#+(Int) and Char#-(Int)
A few bug fixes

0.19.3 (2016-09-30)

crystal eval now accepts some flags like --stats, --release and --help
Added File.chown and File.chmod (thanks @ysbaddaden)
Added Time::Span.zero (useful for doing sum) (thanks @RX14)
Added docs to OAuth and OAuth2
Several bug fixes

0.19.2 (2016-09-16)

Generic type variables no longer need to be single-letter names (for example class Gen(Foo) is now possible)
Added syntax to denote free variables: def foo(x : T) forall T. The old rule of single-letter name still applies but will be removed in the future.
Removed the restriction that top-level types and constants can't have single-letter names
Added @[Extern] attribute to mark regular Crystal structs as being able to be used in C bindings
Faster Char#to_s when it's ASCII: this improves the performance of JSON and CSV parsing
crystal spec: allow passing --release and other options
crystal spec: allow running all specs in a given directory
crystal playground: support custom workbook resources (thanks @bcardiff)
crystal playground: standard output now understands ANSI colors (thanks @bcardiff)
Added many more macro methods to traverse AST nodes (thanks @BlaXpirit)
Error messages no longer include a type trace by default, pass --error-trace to show the full trace (the trace is often useless and makes it harder to understand error messages)
Several bug fixes

0.19.1 (2016-09-09)

Types (class, module, etc.) can now be marked as private.
Added WeakRef (thanks @bcardiff)
Several bug fixes

0.19.0 (2016-09-02)

(breaking change) Added select keyword
(breaking change) Removed $global variables. Use @@class variables instead.
(breaking change) Heredoc now ends when the matching identifier is found, either followed by a space or by a non-identifier
(breaking change) Assignment to a local variable inside an assignment to that same variable is now an error
(breaking change) Type names like T, T1, U, etc., are now disallowed at the top level, to avoid conflicts with free variables
(breaking change) Type lookup (Foo::Bar::Baz) had some incorrect behaviour that now is fixed. This can break existing code that relied on this incorrect behaviour. The fix is to fully qualify types (::Foo::Bar::Baz)
(breaking change) In relationships like class Bar < Foo(Baz) and include Moo(Baz), all of Foo, Moo and Baz must be defined before that point (this was not always the case in previous versions)
(breaking change) Removed the deprecated syntax x as T
(breaking change) Removed block form of String#match
(breaking change) Removed IO#read_nonblock
(breaking change) Int#/ now performs floored division. Use Int#tdiv for truncated division (see their docs to learn the difference)
Added support for LLVM 3.8 (thanks @omarroth)
|| now does type filtering
Generic inheritance should now work well, and (instantiated) generic modules can now be used as the type of instance variables
NamedTuple can now be accessed with strings too (thanks @jhass)
Base64 can now encode and decode directly to an IO (thanks @kostya)
BigInt now uses GMP implementation of gcd and lcm (thanks @endSly)
ECR now supports removing leading and trailing whitespace (<%-, -%>)
HTTP::Request#path now never returns nil: it fallbacks to "/" (thanks @jhass)
String#tr(..., "") is now the same as String#delete
tool hierarchy now supports --format json (thanks @bmulvihill)
Added Char#ascii?
Added Class#nilable? and Union#nilable?
Added Hash#has_value? (thanks @kachick)
Added IO::Sized and IO::Delimited (thanks @RX14)
Added IO::Hexdump (thanks @ysbaddaden)
Added IO#noecho and IO#noecho! (thanks @jhass)
Added Logger.new(nil) to create a null logger
Added OptionParser#missing_option and OptionParser#invalid_option (thanks @jhass)
Added Process.exists?, Process#exists? and Process#terminated? (thanks @jhass)
Added Process.exec (thanks @jhass)
Added Slice#copy_to, Slice#copy_from, Slice#move_to and Slice#move_from (thanks @RX14)
Added URI#== and URI#hash (thanks @timcraft)
Added YAML#parse(IO)
Added Indexable module that Array, Slice, Tuple and StaticArray include
Added indent parameter to to_pretty_json
Added lazy form of getter and property macros
Added macro methods to access an ASTNode's location
Unified String and Char to integer/float conversion API (thanks @jhass)
Lots of bug fixes

0.18.7 (2016-07-03)

The compile command was renamed back to build. The compile command is deprecated and will be removed in a future version
Fibers now can be spawned with a name
ECR macros can now be required with just require "ecr"
Several bugs fixes and enhancements

0.18.6 (2016-06-28)

T? is now parsed as Union(T, Nil) outside the type grammar
Added String#sub overloads for replacing an index or range with a char or string
Several bugs fixes

0.18.5 (2016-06-27)

Added OpenSSL::SSL::Socket#alpn_protocol
Added IO#copy(src, desc, limit) (thanks @jreinert)
Added TypeNode#instance macro method
Several bugs fixes

0.18.4 (2016-06-21)

Fixed #2887
Fix broken specs

0.18.3 (2016-06-21)

TypeNode: added <, <=, > and >= macro methods
Several bugs fixes

0.18.2 (2016-06-16)

Fixed building Crystal from the source tarball

0.18.1 (2016-06-16)

Spec: passing --profile shows the slowest 10 specs (thanks @mperham)
Added StringLiteral#> and StringLiteral#< in macros
Several bugs fixes

0.18.0 (2016-06-14)

(breaking change) IniFile was renamed to INI, and its method load renamed to parse
(breaking change) Process.getpgid was renamed to Process.pgid
(breaking change) An Exception's backtrace is now set when it's raised, not when it's created: it's backtrace method raises if it's not set, and there's backtrace? to get it as a nilable array
(breaking change) dup is now correctly implemented in all types. clone is not defined by default, but some types in the standard library do. Also check Object#def_clone
(breaking change) the method_missing macro only accepts a single argument: a Call now. The form that accepted 3 arguments was removed.
(breaking change) the delegate macro must now be used like delegate method1, method2, ..., methodN, to: object
(breaking change) Hash#each_with_index and Hash#each_with_object now yield a tuple (pair) and an index, because Hash is now Enumerable. Use do |(key, value), index| for this.
(breaking change) {"foo": 1} denotes a named tuple literal now, not a hash literal. Use {"foo" => 1} instead. This also applies to, for example HTTP::Headers{...}
(breaking change) Extra block arguments now give a compile-time error. This means that methods that yield more than once, one time with N arguments and another time with M arguments, with N < M, will always give an error. To fix this, add M - N nil fillers on the yield side (this makes it more explicit that nil was intended to be a block argument value)
(breaking change) OpenSSL::SSL::Context and OpenSSL::SSL::Socket can no longer be used directly anymore. Use their respective subclasses OpenSSL::SSL::Context::Client, with OpenSSL::SSL::Socket::Client, OpenSSL::SSL::Context::Server with OpenSSL::SSL::Socket::Server.
(breaking change) TLS server and client sockets now use sane defaults, including support for hostname verification for client sockets, used by default in HTTP::Client.
(breaking change) The ssl option was renamed to tls in HTTP::Client, HTTP::Server, HTTP::WebSocket, OAuth::Consumer, OAuth::Signature and OAuth2::AccessToken.
The dns_timeout setting in a few classes like HTTP::Client and TCPSocket is now ignored until a next version supports a non-blocking getaddrinfo equivalent
OpenSSL::SSL::Socket::Client supports server name indication now.
The build command was renamed to compile. The build command is deprecated and will be removed in a future version
The --cross-compile flag no longer takes arguments, use --target and -D
Added a Union type that represents the type of a union, which can have class methods
Methods, procs and lib functions that are marked as returning Void now return Nil
Methods that are marked as returning Nil are not checked for a correct return type, they always return nil now
When as fails at runtime it now includes which type couldn't be cast
Macros can now be used inside lib and enum declarations
Macros can now be declared inside enums
Macro calls can now be used as enum values
Generic types can now include a splatted type variable. This already existed in the language (Tuple(*T), Proc(*T)) but there was no syntax to define such types.
Class variables are now inherited (only their type, not their value). They are now similar to Ruby class instance variables.
Splats in yield can now be used
Splat in block arguments can now be used.
Added block auto-unpacking: if a method yields a tuple and a block specifies more then one block argument, the tuple is unpacked to these arguments
String literals are now allowed as external method arguments, to match named tuples and named arguments
sizeof and instance_sizeof can now be used as generic type arguments (mostly useful combined with StaticArray)
Hash, HTTP::Headers, HTTP::Params and ENV now include the Enumerable module
Proc is now Proc(*T, R)
Tuple(*T).new and NamedTuple(**T).new now correctly match the given T (#1828)
Float64#to_s now produces an ever more accurate output
JSON parsing now correctly handle floats with many digits
JSON.mapping and YAML.mapping now also accept named arguments in addition to a hash literal or named tuple literal
Int#chr now raises if the integer is out of a char's range. The old non-raising behaviour is now in Int#unsafe_chr.
The output of pp x is now x # => ... instead of x = ...
The output of the debug() macro method now tries to format the code (pass false to disable this)
Added JSON and YAML parsing and mapping for unions
Added FileUtils.cp_r (thanks @Dreauw)
Added Tuple.from and NamedTuple.from (thanks @jhass)
Added XML.escape (thanks @juanedi)
Added HTTP::Server::Response#respond_with_error (thanks @jhass)
Added TCPServer#accept?
Added optional base argument to Char#digit? and Char#hex? (thanks @mirek)
Added flag? macro method, similar to using ifdef. ifdef is deprecated and will be removed in a future version.
Added YAML::PullParser#read_raw
Added Proc#partial
Added Socket.ip?(str) to validate IPv4 and IPv6 addresses
Added Bytes as an alias of Slice(UInt8)
Added RangeLiteral macro methods: begin, end, excludes_end?, map and to_a
Added ArrayLiteral#[range] and ArrayLiteral#[from, to] in macros (applicable for TupleLiteral too)
Added Generic macro methods: name, type_vars, named_args
Spec: added JUnit formatter output (thanks @juanedi)
The tls option in HTTP::Client can now take a OpenSSL::SSL::Context::Client in addition to true.
HTTP::LogHandler logs exceptions now (thanks @jhass)
HTTP::ErrorHandler does not tell the client which exception occurred by default (can be enabled with a verbose flag) (thanks @jhass)
Several bug fixes

0.17.4 (2016-05-26)

Added string literals without interpolations nor escapes: %q{...} and <<-'HEREDOC'. Also added %Q{...} with the same meaning as %{...}.
A method that uses @type inside a macro expression is now automatically detected as being a macro def
Float64#to_s now produces a more accurate output
Added Crystal::VERSION and other compiler-metadata constants
Added Object.from_json(string_or_io, root) and a root option to JSON.mapping
Added System.hostname (thanks @miketheman)
The property, getter and setter macros now also accept assignments (property x = 0)
The record macro now also accepts assignments (record Point, x = 0, y = 0)
Comparison in macros between MacroId and StringLiteral or SymbolLiteral now work as expected (compares the id representation)
Some bug fixes

0.17.3 (2016-05-20)

Fixed: multiple macro runs executions didn't work well (#2624)
Fixed incorrect formatting of underscore in unpacked block arguments
Fixed wrong codegen for global variable assignment in type declaration (#2619)
Fixed initialize default arguments where evaluated at the class scope (#731)
The type guesser can now infer a block type from def initialize(&@block)
Allow type restriction in double splat argument (similar to restriction in single splat)
Allow splat restriction in splat argument (useful for Tuple.new)
Allow double splat restriction in double splat argument (useful for NamedTuple.new)

0.17.2 (2016-05-18)

Fixed crash when using pointerof of constant

0.17.1 (2016-05-18)

Constants and class vars are no longer initialized before "main". Now their initialization order goes along with "main", similar to how it works in Ruby (much more intuitive)
Added syntax for unpacking block arguments: foo { |(x, y)| ... }
Added NamedTupleLiteral#map and HashLiteral#map in macros (thanks @jhass)
Fixed wrong codgen for tuples/named tuples merge with pass-by-value types
Formatter: fixed incorrect format for named tuple type

0.17.0 (2016-05-17)

(breaking change) Macro defs are now parsed like regular methods. Enclose the body with {% begin %} .. {% end %} if you needed that behaviour
(breaking change) A union of two tuples of the same size results in a tuple with the unions of the types in each position. This only affects code that later tested a tuple's type with is_a?, for example tuple.is_a?({Int32, String})
(breaking change) Method arguments have now a different semantic. This only affects methods that had a splat argument followed by other arguments.
(breaking change) The syntax {foo: 1, bar: 2} now denotes a NamedTuple, not a Hash with symbol as keys. Use {:foo => 1, :bar => 2} instead
The syntax exp as Type is now deprecated and will be removed in the next version. Use crystal tool format to automatically upgrade your code
The compiler now gives an error when trying to define a method named !, is_a?, responds_to?, nil?, as or as?
Added the NamedTuple type
Added double splatting
Added external argument names
Macro defs return type is no longer mandatory
Added as?: similar to as, but returns nil when the type doesn't match
Added Number::Primitive alias
Added Tuple#+(Tuple)
Added ArrayLiteral#+(ArrayLiteral) in macros
Crypto::MD5 now allows Slice(UInt8) and a block form (thanks @will)
Added docs for XML (thanks @Hamdiakoguz)
Many bug fixes

0.16.0 (2016-05-05)

(breaking change) Instance, class and global variables types must be told to the compiler, either explicitly or through a series of syntactic rules
(breaking change) Non-abstract structs cannot be inherited anymore (abstract structs can), check the docs to know why. In many cases you can use modules instead.
(breaking change) Class variables are now initialized at the beginning of the program (before "main"), make sure to read the docs about class variables and main
(breaking change) Constants are now initialized at the beginning of the program (before "main"), make sure to read the docs about constants and main
(breaking change) When doing crystal program.cr arg1 arg2 arg3, arg1, arg2 and arg3 are considered arguments to pass to the program (not the compiler). Use crystal run program.cr arg1 ... to consider arg1 a file to include in the compilation.
(breaking change) Int#**(Int) now returns an integer, and raises if the argument is negative. Use a float base or exponent for negative exponents to work.
(breaking change) Slice#to_s and StaticArray#to_s now include their type name in the output
Support for FreeBSD and musl libc has landed (thanks @ysbaddaden)
The .crystal directory is now created at $HOME/.cache/crystal or $HOME/.crystal (or others similar), with a fallback to the current directory
crystal doc and crystal tool hierarchy are now much faster. Additionally, the hierarchy tool shows types for generic types, and doesn't show instantiations anymore (wasn't very useful)
! now does type filtering (for example you can do !x || x.bar, assuming x can be nil and the non-nil type responds to bar)
Named arguments can now match any argument, even if they don't have a default value. Make sure to read the docs
The as operator can now be written as a method: exp.as(Type) in addition to exp as Type. The old syntax will be removed in a few releases.
Added @x : Int32 = 1 syntax (declaration + initialization)
new/initialize logic now works more as one would expect
Added BigRational (thanks @will)
Added BigFloat (thanks @Exilor)
Added String#insert
Added Time::EpochConverter and Time::EpochMillisConverter
Added %s (unix epoch) directive to Time::Format
Time now honours Dayling Saving and ENV["TZ"]
Added HTTP::Server::Response#cookies (thanks @jhass)
Added Array#bsearch, Array#bsearch_index and Range#bsearch (thanks @MakeNowJust)
Added Range#reverse_each iterator (thanks @omninonsense)
JSON::Any: added as_...? methods (thanks @DougEverly)
JSON::Any is now Enumerable
YAML::Any is now Enumerable
Added JSON.parse_raw that returns a JSON::Type
JSON::PullParser: added #read_raw to read a JSON value as a raw string (useful for delayed parsing). Also added String::RawConverter to be used with JSON.mapping.
JSON and YAML: enums, BigInt and BigFloat are now serializable
ENV: allow passing nil as a value to delete an environment variable
Hash: allow Array | Tuple arguments for #select, #select!, #reject and #reject!
Crypto::Subtle.constant_time_compare now returns Bool, and it can compare two strings in addition to two slices (thanks @skunkworker)
HTTP::Server: reset port zero after listening (thanks @splattael)
Added File#each_line iterator
Added Number.slice, Number.static_array, Slice.[] and StaticArray.[] to easily create slices and static arrays
Added Slice#hexdump (thanks @will)
Added Enumerable#product (thanks @dkhofer)
Fix: disallow using out with Void* pointers
Fixed bug in XML::Node#namespace_scopes (thanks @Hamdiakoguz)
Added docs for INIFile (thanks @EvanHahn)
Lots of bug fixes

0.15.0 (2016-03-31)

(breaking change) ! has now its meaning hardcoded in the language. If you defined it for a type it won't be invoked as a method anymore.
(breaking change) nil? has now its meaning hardcoded in the language. If you defined it for a type it won't be invoked as a method anymore.
(breaking change) typeof is now disallowed in alias declarations
Added crystal tool format --check to check that source code is properly formatted
crystal play (playground) added workbooks support, as well as improvements and stabilizations
Added Tempfile.dirname (thanks @DougEverly)
Added Path#resolve method in macros
{{...}} arguments to a macro call are now expanded before macro invocation (#2392)
Special variables ($~ and $?) are now accessible after being defined in blocks (#2194)
Some bugs and regressions fixed

0.14.2 (2016-03-22)

Fixed regression with formatter (#2348)
Fixed regression with block return types (#2347)
Fixed regression with openssl (https://github.com/crystal-lang/crystal/commit/78c12caf2366b01f949046e78ad4dab65d0d80d4)

0.14.1 (2016-03-21)

Fixed some regressions in the formatter

0.14.0 (2016-03-21)

(breaking change) The syntax of a method argument with a default value and a type restriction is now def foo(arg : Type = default_value). The old def foo(arg = default_value : Type) was removed.
(breaking change) Enumerable#take(n) and Iterator#take(n) were renamed to first(n)
(breaking change) Socket#addr and Socket#peeraddr were renamed to local_address and remote_address respectively
(breaking change) Removed Comparable#between?(a, z). Use a <= x <= z instead
(breaking change) HTTP::WebSocketHandler callbacks can now access the HTTP::Context. If you had a forwarding method to it you'll need to update it. See #2313.
New command crystal play that opens a playground for you to play in the browser :-) (thanks @bcardiff)
New command crystal env that prints environment information
Spec: you can now run multiple files with specified line numbers, as in crystal spec file1.cr:10 file2.cr:20 ...
Initial support for musl-libc (thanks @ysbaddaden)
Added FileUtils.cp (thanks @Dreauw)
Added Array#first(n) and Array#last(n) (thanks @greyblake)
Added WebSocket#close and properly handle disconnections
Added UDPSocket#send and UDPSocket#receive (thanks @tatey)
Added Char#uppercase? and Char#lowercase? (thanks @MaloJaffre`)
Added sync_close property to OpenSSL::SSL::Socket, Zlib::Inflate and Zlib::Deflate
Added XML::Node#encoding and XML::Node#version
Added HTTP::Client::Response#success? (thanks @marceloboeira)
Added StaticArray#shuffle!(random) (thanks @Nesqwik)
Added Splat#exp method in macros
Added fiber-safe Mutex
All Int types (except BigInt) can now be used in JSON and YAML mappings (thanks @marceloboeira)
Instance variable declarations/initializations now correctly work in generic classes and modules
Lots of bug fixes

0.13.0 (2016-03-07)

(breaking change) Matrix was moved to a separate shard: https://github.com/Exilor/matrix
The syntax of a method argument with a default value and a type restriction is now def foo(arg : Type = default_value). Run crystal tool format to automatically upgrade existing code to this new syntax. The old def foo(arg = default_value : Type) syntax will be removed in a next release.
Special handling of case with a tuple literal. See #2258.
Keywords can now be used for variable declaration, so property end : Time works as expected.
Comparison of signed vs. unsigned integers now always give a correct result
Allow declaring instance variables in non-generic module types (module Moo; @x : Int32; end)
Allow initializing instance variables in non-generic module types (module Moo; @x = 1; end)
Spec: allow setting multiple output formatters (thanks @marceloboeira)
StringScanner: improved performance
Added foo.[0] = 1 and foo.[0] as valid syntax, similar to the one in &. blocks (thanks @MakeNowJust)
CSV: allow separate and quote characters different than comma and doble quote (thanks @jreinert)
YAML: support merge operator (<<) (thanks @jreinert)
Allow redefining primitive methods like Int32#+(other : Int32)
Allow defining macros with operator names like []
Levenshtein: improved performance (thanks @tcrouch)
HTTP::Client: fixed incorrect parsing of chunked body
HTTP::Client: added a constructor with an URI argument (thanks @plukevdh)
String: sub and gsub now understand backreferences (thanks @bjmllr)
Random: added Random#rand(Float64) and Random#rand(Range(Float, Float)) (thanks @AlexWayfer)
HTML: HTLM.escape includes more characters (thanks @Ryuuzakis)
Added TypeNode.class method in macros (thanks @waterlink)
run inside macros now also work with absolute paths (useful when used with __DIR__)
Added docs for Math and StaticArray (thanks @Zavydiel, @HeleneMyr)
Many bug fixes and some micro-optimizations

0.12.0 (2016-02-16)

(breaking change) When used with a type declaration, the macros property, getter, setter, etc., declare instance variables with those types.
(breaking change) JSON.mapping and YAML.mapping declare instance variables with the given types.
(breaking change) YAML.load was renamed to YAML.parse, and it now returns a YAML::Any.
(breaking change) embed_ecr and ecr_file were renamed to ECR.embed and ECR.def_to_s (the old methods now produce a warning and will be removed in the next release).
Added encoding support: IO#set_encoding, String#encode, and HTTP::Client charset check.
Segmentation faults are now trapped and shown in a more friendlier way.
The record macro can now accept type declarations (for example record Point, x : Int32, y : Int32)
Added Iterator#step (thanks @jhass)
Array#push and Array#unshift can now accept multiple values and add the elements in an efficient way (thanks @arktisklada)
Added default option to JSON.mapping (thanks @kostya)
Added default option to YAML.mapping (thanks @jreinert)
Allow doing case foo; when Foo.class (and Foo(T) and Foo(T).class) in case expressions.
Added Class#| so a union type can be expresses as Int32 | Char in regular code.
Added File.real_path (thanks @jreinert)
Added dns_timeout for HTTP::Client (thanks @kostya)
Added dynamic width precision to sprintf (thanks @gtramontina)
Markdown now supports blockquotes and 1 level of list nesting (thanks @SebastianSzturo)
p now accepts multiple arguments
Many bug fixes and some optimizations

0.11.1 (2016-01-25)

Fixed #2050, #2054, #2057, #2059, #2064
Fixed bug: HTTP::Server::Response headers weren't cleared after each request
Formatter would incorrectly change property x :: Int32 to property x = uninitialized Int32

0.11.0 (2016-01-23)

(breaking change) Syntax for type declarations changed from var :: Type to var : Type. The old syntax is still allowed but will be deprecated in the next version (run crystal tool format to automatically fix this)
(breaking change) Syntax for uninitialized variables, which used to be var :: Type, is now var = uninitialized Type. The old syntax is still allowed but will be deprecated in the next version (run crystal tool format to automatically fix this)
(breaking change) HTTP::Server refactor to support streaming. Check the docs of HTTP::Server for upgrade instructions
(breaking change) Renamed HTTP::WebSocketSession to HTTP::WebSocket.
(breaking change) Heredocs now remove indentations according to the indentation of the closing identifier (thanks @rhysd)
(breaking change) Renamed Enumerable#inject to Enumerable#reduce
(breaking change) next and return semantic inside captured block has been swapped (#420)
Fibers context switch is now faster, done with inline assembly. libpcl is no longer used
Allow annotating the type of class and global variables
Support comments in ECR (thanks @ysbaddaden)
Security improvements to HTTP::StaticFileHandler (thanks @MakeNowJust)
Moved seek, tell, pos and pos= from File to IO::FileDescriptor (affects Tempfile)
URI.parse is now faster (thanks @will)
Many bug fixes, some really old ones involving issues with order of declaration

0.10.2 (2016-01-13)

Fixed Directory Traversal Vulnerability in HTTP::StaticFileHandler (thanks @MakeNowJust)

0.10.1 (2016-01-08)

Added Int#popcount (thanks @rmosolgo)
Added @[Naked] attribute for omitting a method's prelude
Check that abstract methods are implemented by subtypes
Some bug fixes

0.10.0 (2015-12-23)

(breaking change) def arguments must always be enclosed in parentheses
(breaking change) A space is now required before and after def return type restriction
(breaking change) Renamed Dir.working_dir to Dir.current
(breaking change) Moved HTML::Builder to its own shard
(breaking change) String#split now always keeps all results (never drops trailing empty strings)
(breaking change) Removed Array#buffer, StaticArray#buffer and Slice#buffer. Use to_unsafe instead (so unsafe usages are easier to spot)
(breaking change) Removed String#cstr. Use to_unsafe instead (so unsafe usages are easier to spot)
Optimized Range#sum (thanks @MakeNowJust)
Allow forward declarations for lib external vars
Added Int#to_s(base) for base = 62 (thanks @jhass)
JSON.parse now returns JSON::Any, which allows traversal of JSON objects with less casts
Added OpenSSL::PKCS5 (thanks @benoist)
MemoryIO can now be created to read/write from a Slice(UInt8). In this mode MemoryIO can't be exapnded, and can optionally be written. And when creating a MemoryIO from a String, it's non-resizeable and read-only.
Added Object#!~ (the opposite of =~)
at_exit now receives that exit status code in the block (thanks @MakeNowJust)
Allow using Set in JSON mappings (thanks @benoist)
Added File.executable?, File.readable? and File.writeable? (thanks @mverzilli)
Array#sort_by and Array#sort_by! now use a Schwartzian transform (thanks @radarek)
Added Array#each_permutation, Array#each_combination and Array#each_repeated_combination iterators
Added optional random argument to Array#sample and Array#shuffle
The delegate macro can now delegate multiple methods to an object (thanks @elthariel)
Added basic YAML generation (thanks @porras)

0.9.1 (2015-10-30)

Docs search now finds nested entries (thanks @adlerhsieh)
Many corrections and changes to the formatter, for better consistency and less obtrusion.
Added OpenSSL::Cipher and OpenSSL::Digest (thanks @benoist)
Added Char#+(String) (thanks @hangyas)
Added Hash#key and Hash#key? (thanks @adlerhsieh)
Added Time::Span#* and Time::Span#/ (thanks @jbaum98)
Added Slice#reverse_each (thanks @omninonsense)
Added docs for Random and Tempfile (thanks @adlerhsieh)
Fixed some bugs.

0.9.0 (2015-10-16)

(breaking change) The CGI module's funcionality has been moved to URI and HTTP::Params
(breaking change) IO#read() is now IO#gets_to_end. Removed IO#read(count), added IO#skip(count)
(breaking change) json_mapping is now JSON.mapping. yaml_mapping is now YAML.mapping
(breaking change) StringIO is now MemoryIO
Added crystal tool format that automatically formats your code
protected methods can now be invoked between types inside a same namespace
Removed curses, you can use https://github.com/jreinert/ncurses-crystal
to_unsafe and numeric conversions are now also automatically performed in C struct and union fields
Added {% begin %} ... {% end %} as an alternative to {% if true %} ... {% end %}
Added ~! operator
Added debug metadata for char, float, bool and enums. Also for classes and structs (experimental)
Dir.glob now works well with recursive patterns like ** (thanks @pgkos)
Added read_timeout and connect_timeout to HTTP::Client (thanks @benoist)
Added Zlib (thanks @datanoise and @bcardiff)
Added HTTP::DeflateHandler (thanks @bcardiff)
Added ENV#fetch (thanks @tristil)
Hash#new now accepts an initialize capacity argument
HTTP::Request provides access and mutation of query, path and query_params (thanks @waterlink)
Added XML::Node#content= and #name=
Allow passing handlers and a block to an HTTP::Server (thanks @RX14)
crystal init now tries to use your github username if available (thanks @jreinert)
Added Hash#select, Hash#reject and their bang variant, and Hash#each_with_object (thanks @devdazed)
Added Hash#select(*keys) and Hash#reject(*keys) and their bang variant (thanks @sdogruyol)
Added Set#-, Set#^, and Set#subtract (thanks @js-ojus)
Allow running specs without colors (thanks @rhysd)
Added TypeNode#has_constant? and TypeNode#type_vars in macros (thanks @jreinert)
Added String#compare that allows case insensitive comparisons
Added File#truncate (thanks @porras)
CSV is now a class for iterating rows, optionally with headers access
Allow setting multiple before_request callbacks to an HTTP::Client
Added Dir.cd(&block) (thanks @rhysd)
Added Class#cast (thanks @will)
Fixes and additions to WebSocket, like the possibility of streaming data (thanks @jreinert)
Added SemanticVersion class (thanks @technorama)
loop now yields a counter
Added Array#[]=(index, count, value) and Array#[]=(range, value)
Added argless sleep
IO#write(slice) now writes the full slice or raises on error
Added some docs for ECR, Markdown, Hash, File, Time, Time::Span, Colorize, String, SecureRandom, YAML (thanks @adlerhsieh, @chdorner, @vjdhama, @rmosolgo)
Many bug fixes

0.8.0 (2015-09-19)

(breaking change) Renamed a couple of types: ChannelClosed -> Channel::ClosedError, UnbufferedChannel -> Channel::Unbuffered, BufferedChannel -> Channel::Buffered, DayOfWeek -> Time::DayOfWeek, MonthSpan -> Time::MonthSpan, TimeSpan -> Time::Span, TimeFormat -> Time::Format, EmptyEnumerable -> Enumerable::EmptyError, SocketError -> Socket::Error, MatchData -> Regex::MatchData, SignedInt -> Int::Signed, UnsignedInt -> Int::Unsigned, FileDescriptorIO -> IO::FileDescriptor, BufferedIO -> IO::Buffered, CharReader -> Char::Reader, PointerAppender -> Pointer::Appender.
(breaking change) All places that raised DomainError raise ArgumentError now.
(breaking change) Renamed Type.cast to Type.new (for example, Int32.new instead of Int32.cast)
(breaking change) Removed all macro instance variables except @type
(breaking change) Removed undef
(breaking change) Removed length() and count() methods from collections. The only method for this is now size.
(breaking change) Removed the ability to invoke methods on a union class
Improved debugger support
crystal deps now delegates to shards. Removed Projecfile support.
Automatically convert numeric types when invoking C functions
Automatically define questions methods for enum members
Support quotes inside quoted symbols (thanks @wolflee)
Allow marking initialize as private
Added method_added macro hook (thanks @MakeNowJust)
Added ArrayLiteral#includes?(obj) in macros
Added ASTNode#symbolize in macros (thanks @kirbyfan64)
Added experimental yaml_mapping
Added nilable variants to Enumerable#max, Enumerable#min, and others (thanks @technorama)
Added Iterator#flatten (thanks @jpellerin)
Added setting a read timeout to HTTP::Client (thanks @benoist)
Added Array#delete_at(index, count) and Array#delete_at(range) (thanks @tebakane)
Added HTTP::Cookies (thanks @netfeed)
Added Tuple#reverse (thanks @jhass)
Added Number#clamp (thanks @technorama)
Added serveral socket options (thanks @technorama)
Added WebSocket.open (thanks @kumpelblase2)
Added Enum.flags macro
Added support for sending chunked content in HTTP server (thanks @bcardiff)
Added future, lazy and delay concurrency methods (thanks @technorama)
fork now returns a Process (thanks @technorama)
Documented Set, and added a couple of methods (thanks @will)
Nicer formatting in Benchmark.ips, and interactive mode (thanks @will)
The -f format output is now honored in compiler errors (thanks @kirbyfan64)
Fixed an ambiguity with the crystal build command (thanks @MakeNowJust)
Cast exceptions now raise TypeCastError instead of Exception (thanks @will)
Many bugs fixes

0.7.7 (2015-09-05)

(breaking change) Reimplemented Process.run to allow configuring input, output and error, as well as behaving well regarding non-blocking IO (thanks @technorama)
(breaking change) Removed the alias_method macro.
(breaking change) Disallow declaring defs, classes and other declarations "dynamically" (for example inside an if... this of course didn't work, but incorrectly compiled).
(breaking change) require is now only allowed at the top-level, never inside other types or methods.
(breaking change) Removed Nil#to_i
(breaking change) Changed API of Channel#select toward a thread-safe one.
(breaking change) The two methods that IO must implement are now read(slice : Slice(UInt8)) and write(slice : Slice(UInt8)).
New beautiful, searchable and more functional API docs. Thanks @rosylilly for the initial design, and @BlaxPirit for some improvements.
CLI: Moved browser, hierarchy and types to crystal tool ...
Added crystal tool context and crystal tool implementations for IDEs (thanks @bcardiff!!)
Int#>>(amount) and Int#<<(amount) now give zero when amount is greater than the number of bits of the integer representation.
Added \% escape sequence inside macros.
Added aliases for the many C types (thanks @BlaxPirit)
Added Iterator#in_groups_of (thanks @PragTob)
Added optional offset argument to Hash#each_with_index (thanks @sergey-kucher)
Added Array#combinations, Array#each_combination, Array#repeated_combinations, Array#each_repeated_combination, Array#repeated_permutations, Array#each_repeated_permutation, Array.product and Array.each_product (thanks @kostya)
Added Array#rotate and Array#rotate! (thanks @kostya)
Added MatchData#pre_match and MatchData#post_match (thanks @bjmllr)
Added Array#flatten
Added Range.reverse_each, along with Int#pred and Char#pred (thanks @BlaxPirit)
Added XML.parse_html (thanks @ryanworl)
Added ENV.keys andENV.values (thanks @will)
Added StaticArray==(other : StaticArray) (thanks @tatey)
Added String#sub in many variants (thanks @jhass)
Added Readline.bind_key, Readline.unbind_key, Readline.done and Readline.done= (thanks @daphee)
Added Hash#all?, Hash#any? and Hash#inject (thanks @jreinert)
Added File#pos and File#pos=
Added Enum.from_value and Enum.from_value?
Added Deque (thanks @BlaxPirit)
Added lots of methods to StringScanner, and documented it, making it usable (thanks @will)
StringIO now quacks like a File.
Allow sending masked data through a WebSocket, and sending long data (thanks @kumpelblase2)
File.new now accepts an optional perm argument (thanks @technorama)
FileDescriptorIO now has configurable read/write timeouts (thanks @technorama)
Signal handling is more robust and allows any kind of code (thanks @technorama)
Correctly handle WebSocket close packet (thanks @bebac)
Correctly implement seek and tell in buffered IOs (thanks @lbguilherme)
Allow setting several options on sockets (thanks @technorama)
Some improvements to crystal init for the "app" case (thanks @krisleech)
sleep and IO timeouts can receive TimeSpan as arguments (thanks @BlaxPirit)
Handle HTTP::Response without content-length (thanks @lbguilherme)
Added docs for OptionParser, ENV, Regex, Enumerable, Iterator and some Array methods (thanks @porras, @will, @bjmllr, @PragTob, @decioferreira)
Lots of bug fixes and small improvements

0.7.6 (2015-08-13)

(breaking change) removed support for trailing while/until (read this)
(breaking change) Renamed Enumerable#drop to Enumerable#skip
(breaking change) Renamed Time.at to Time.epoch, and Time#to_i and Time#to_f to Time#epoch and Time#epoch_f
(breaking change) inherited macro now runs before a class' body
Renamed --no-build flag to --no-codegen
Allow interpolations in heredocs (thanks @jessedoyle)
Allow hash substitutions in String#% and sprintf (thanks @zamith)
Added SecureRandom.base64, SecureRandom.urlsafe_base64 and SecureRandom.uuid (thanks @ysbaddaden)
Added File.link, File.symlink and File.symlink? (thanks @ysbaddaden)
Added Enumerable#in_groups_of (thanks @jalyna)
Added Array#zip? (thanks @yui-knk)
Added Array#permutations and Array#each_permutation (thanks @jalyna and @kostya)
Added IO#gets(limit : Int) and IO#gets(delimiter : Char, limit : Int)
Added Iterator#compact_map, Iterator#take_while and Iterator#skip_while (thanks @PragTob)
Added StringLiteral#to_i macro method
Added Crypto::Bcrypt (thanks @akaufmann)
Added Time.epoch_ms and Time#epoch_ms
Added BitArray#toggle and BitArray#invert (thanks @will)
Fixed IO#reopen swapped semantic (thanks @technorama)
Many bug fixes and improvements

0.7.5 (2015-07-30)

(breaking change) 0 is not a prefix for octal numbers anymore. Use 0o
(breaking change) Renamed MissingKey to KeyError
(breaking change) Renamed IndexOutOfBounds to IndexError
Fixed all exception-handling related bugs.
Allow nested and multiline ternary expressions (thanks @daviswahl)
Allow assigning to _ (underscore), give error when trying to read from it
Macros can now also receive the following nodes: And, Or, Case, RangeLiteral and StringInterpolation. And and Or have left and right methods.
Added -e option to hierarchy command to filter types by a regex
Added -v as an alias of --version
Added -h as an alias of --help
Added Array#transpose (thanks @rhysd)
Added Benchmark#ips (thanks @will)
Added Hash#merge(&block) and Hash#merge!(&block) (thanks @yui-knk)
Added Hash#invert (thanks @yui-knk)
Added Bool#^ (thanks @yui-knk)
Added Enumerable#drop, Enumerable#drop_while and Enumerable#take_while (thanks @PragTob)
Added Enumerable#none? (thanks @yui-knk)
Added Set#subset?, Set#superset? and Set#intersects? (thanks @yui-knk)
Added Set#new(Enumerable) (thanks @yui-knk)
Added String#succ (thanks @porras and @Exilor)
Added Array#* (thanks @porras)
Added Char#===(Int) and Int#===(Char) (thanks @will)
Added StringLiteral#camelcase and StringLiteral#underscore in macros
Added Expressions#expressions in macros
Added Cast#obj and Cast#to in macros
Added ASTNode#class_name in macros (thanks @yui-knk)
Added Array#push/Array#<< and Array#unshift in macros (thanks @ysbaddaden)
Added Def#visibility in macros (thanks @ysbaddaden)
Added String#codepoints and String#each_codepoint (thanks @jhass)
Char#to_i(base) now supports bases from 2 to 36
Set#| now correctly accepts a set of a possible different type (thanks @yui-knk)
Flush STDERR on exit (thanks @jbbarth)
HTTP::Client methods accept an optional block, which will yield an HTTP::Response with a non-nil body_io property to consume the response's IO
Document URI, UDPSocket (thanks @davydovanton)
Improved URI class (thanks @will)
Define $~ in String#gsub and String#scan
Define $? in Process.run
Lots of bug fixes and small improvements

0.7.4 (2015-06-23)

Added Float module and remainder (thanks @wmoxam)
Show elapsed time in HTTP::LogHandler (thanks @zamith for the suggestion)
Added 0o as a prefix for octal numbers (thanks @asb)
Allow spaces before the closing tag of a heredoc (thanks @zamith)
String#split(Regex) now includes captures in the results
Added union?, union_types and type_params in macro methods
Improved MatchData#to_s to show named groups (thanks @will)
Optimized Base64 encode/decode (thanks @kostya)
Added basic docs for spec (thanks @PragTob)
Added docs for Benchmark (thanks @daneb)
Added ARGF
Non-matching regex captures now return nil instead of an empty string (thanks @will)
Added $1?, $2?, etc., as a nilable alternative to $1, $2, etc.
Added user, password, fragment and opaque to URI (thanks @will)
HTTP::Client.exec now honors user/password info from URI
Set default user agent in HTTP::Client
Added String#chop
Fixed crystal deps behaviour with empty git repositories (thanks @tkrajcar)
Optimized HTTP::Headers and HTTP::Request parsing.
FileDescriptorIO (superclass of File and Socket) has now buffering capabilities (use sync= and sync? to turn on/off). That means there's no need to use BufferedIO for these classes anymore.
Allow pointerof with class and global variables, and also foo.@bar access
Optimized fibers performance.
Added inline assembly support.
The .crystal cache dir is now configurable with an ENV variable (thanks @jhass)
Generic type variables names can now also be a single letter followed by a digit.

0.7.3 (2015-06-07)

Added Tuple.from_json and Tuple.to_json
The method_missing macro now accepts a 1 argument variant that is a Call node. The 3 arguments variant will be deprecated.
Flush STDOUT at program exit (fixes print not showing any output)
Added Time#to_utc and Time#to_local (thanks @datanoise)
Time comparison is now correct when comparing local vs. utc times
Support timezone offsets in Time parsing and formatting
Added IO#gets(delimiter : String)
Added String#chomp(Char) and String#chomp(String)
Allow invoking debug() inside a macro to see what's being generated.
IO#puts and IO#print now receive a splat (thanks @rhysd)
Added Process.kill and Process.getpgid (thanks @barachy)
Signal is now an enum. Use it like Signal::INT.trap { ... } instead of Signal.trap(Signal::INT) { ... }
Added CSV.each_row (both in block and iterator forms)
Important fixes to non-blocking IO logic.

0.7.2 (2015-05-26)

Improved performance of Regex
Fixed lexing of octal characters and strings (thanks @rhysd)
Time.parse can return UTC times (thanks @will)
Handle dashes in crystal init (thanks @niftyn8)
Generic type variables can now only be single letters (T, U, A, B, etc.)
Support %x and %X in sprintf (thanks @yyyc514)
Optimized Int#to_s (thanks @yyyc514)
Added upcase option to Int#to_s, and use downcase by default.
Improved String#to_i and fixed the many variants (to_i8, to_u64, etc.)
Added Time.at (thanks @jeromegn)
Added Int#upto, Int#downto, Int#to iterators.
Added Iterator#cons and Enumerable#each_cons (thanks @porras)
Added Iterator.of, Iterator#chain and Iterator#tap.
Allow top-level private macro (similar to top-level private def)
Optimized BufferedIO writing performance and memory usage.
Added Channel#close, Channel#closed?, Channel#receive? and allow them to send/receive nil values (thanks @datanoise).
Fixed Process#run after introducing non-blocking IO (thanks @will)
Tuple#map now returns a Tuple (previously it returned an Array)
Tuple#class now returns a proper Class (previously it returned a Tuple of classes)
Lots of bug fixes.

0.7.1 (2015-04-30)

Fixed #597.
Fixed #599.

0.7.0 (2015-04-30)

Crystal has evented IO by default. Added spawn and Channel.
Correctly support the X86_64 and X86 ABIs. Now bindings to C APIs that pass and return structs works perfectly fine.
Added crystal init to quickly create a skeleton library or application (thanks @waterlink)
Added --emit flag to the compiler. Now you can easily see the generated LLVM IR, LLVM bitcode, assembly and object files.
Added --no-color flag to suppress color output, useful for editor tools.
Added macro vars: %var and %var{x, y} create uniqely named variables inside macros.
Added typed splats.
Added Iterator and many methods that return iterators, like Array#each, Hash#each, Int#times, Int#step, String#each_char, etc.
Added sprintf and improved String#% to support floats and float formatting.
Added more variants of String#gsub.
Added Pointer#clear and use it to clear an Array's values when doing pop and other shrinking methods.
Added BigInt#to_s(base), BigInt::cast and bit operators (thanks @Exilor)
Allow invoking methods on a union class as long as all types in the union have it.
Allow specifying a def's return type. The compiler checks the return type only for that def for now (not for subclasses overrding the method). The return type appears in the documentation.
Allow constants and computed constants for a StaticArray length.
Allow class vars in enums.
Allow private and protected defs in enums.
Allow reopening a lib and adding more @[Link] attributes to it, even allowing duplicated attributes.
Allow getting a function pointer to a lib fun without specifying its types (i.e. ->LibC.getenv)
Allow specifying ditto for a doc comment to reuse the previous comment.
Changed the semantic of %: previously it meant remainder, not it means modulo, similar to Ruby and Python. Added Int#remainder.
#to_s and #inspect now work for a union class.
Spec: added global before_each and after_each hooks, which will simplify the use of mocking libraries like timecop.cr and webmock.cr.
Range(T) is now Range(B, E) again (much more flexible).
Improved Regex performance.
Better XML support.
Support LLVM 3.6.
Exception class is now shown on unhandled exceptions
The following types are now disallowed in generics (for now): Object, Value, Reference, Number, Int and Float.
Lots of bug fixes, enhancements and optimizations.

0.6.1 (2015-03-04)

The class method now works in all cases. You can now compare classes with == and ask their hash value.
Block variables can now shadow local variables.
Range(B, E) is now Range(T).
Added Number::[]. Now you can do Int64[1, 2, 3] instead of [1_i64, 2_i64, 3_u64].
Better detection of nilable instance variables, and better error messages too.
Added Crypto::Blowfish (thanks @akaufmann)
Added Matrix (thanks @Exilor)
Added CallConvention attribute for funs.
Macros: added constants so you can inspect a type's constants at compile time.
Macros: added methods, which lists a type's methods (without including supertypes).
Macros: added has_attribute? for enum types, so you can check if an enum has the Flags attribute on it.
Many more small additions and bug fixes.

0.6.0 (2015-02-12)

Same as 0.5.10

0.5.10 (transitional) (2015-02-12)

Note: This release makes core, breaking changes to the language, and doesn't work out of the box with its accompanying standard library. Use 0.6.0 instead.
Improved error messages related to nilable instance variables.
The magic variables $~ and $? are now method-local and concurrent-safe.
Tuple is now correctly considered a struct
Pointer is now correctly considered a struct
Renamed Function to Proc

0.5.9 (2015-02-07)

Random is now a module, with static methods that default to the Random::MT19937 class.
Added Random::ISAAC engine (thanks @ysbaddaden!)
Added String#size (thanks @zamith!)
Added limit to all String#split variants (thanks @jhass!)
Raising inside a Thread is now rescued and re-raised on join (thanks @jhass!)
Added path option to Projectfile for crystal deps (thanks @naps62!)
Many fixes towards making Crystal work on linux 32 bits.
Huge refactors, additions and improvements for sockets: Socket, IPSocket, TCPSocket, TCPServer, UDPSocket, UNIXSocket, UNIXServer (thanks @ysbaddaden!)
Allow regex with empty spaces in various places.
Added HTML.escape(String) (thanks @naps62!)
Added support for %w[...], %w{...}, %w<...> as alternatives to %w(...). Same goes for %i(...) (thanks @zamith!)
Added Enumerable#min_of, Enumerable#max_of and Enumerable#minmax_of, Enumerable#to_h, Dir.chdir and Number#fdiv (thanks @jhass!)
Added String#match, String#[], String#[]? and MatchData#[]? related to regexes (thanks @jhass!)
Allow T::Bar when T is a generic type argument.
Added subclasses and all_subclasses in macros.
Now you can invoke to_s and inspect on C structs and unions, making debugging C bindings much easier!
Added #to_f and #to_i to Time and TimeSpan (thanks @epitron!)
Added IO.select (thanks @jhass!)
Now you can use ifdef inside C structs and unions.
Added include inside C structs, to include other struct fields (useful for composition and avoiding an explicit indirection).
Added Char#in_set?, String#count, String#delete and String#squeeze (thanks @jhass!)
Added -D flag option to the compiler to set compile-time flags to use in ifdef.
More support for forward declarations inside C libs.
Rewritten some Function primitives in Crystal itself, and added methods for obtaining the pointer and closure data, as well as for recreating a function from these.
Added a Logger class (thanks @ysbaddaden!)
Lots of bugs fixed.

0.5.8 (2015-01-16)

Added Random and Random::MT19937 (Mersenne Twister) classes (thanks @rhysd).
Docs: removed automatic linking. To link to classes and methods surround with backticks.
Fixed #328: != bug.

0.5.7 (2015-01-02)

Fixed: doc command had some hardcoded paths and didn't work
Added: private def at the top-level of a file is only available inside that file

0.5.6 (2014-31-12)

Added a crystal doc command to automatically generate documentation for a project using Markdown syntax. The style is still ugly but it's quite functional. Now we only need to start documenting things :-)
Removed the old @: attribute syntax.
Fixed #311: Issues with invoking lib functions in other ways (thanks @scidom).
Fixed #314: NoReturn information is not lazy.
Fixed #317: Fixes in UTF-8 encoding/decoding (thanks @yous).
Fixed #319: Unexpected EOF (thanks @Exilor).
{{yield}} inside macros now preserve the yielded node location, leading to much better error messages.
Added Float#nan?, Float#infinite? and Float#finite?.
Many other bug fixes and improvements.

0.5.5 (2014-12-12)

Removed src and crystal compiler libs directory from CRYSTAL_PATH.
Several bug fixes.

0.5.4 (2014-12-04)

(breaking change) require "foo" always looks up in CRYSTAL_PATH. require "./foo" looks up relative to the requiring file.
(breaking change) Renamed Json to JSON, Xml to XML and Yaml to YAML to follow a convention.
(breaking change) To use HTTP types do, for example, require "http/client" instead of the old require "net/http".
Added alias_method macro (thanks @Exilor and @jtomschroeder).
Added some Complex number methods and many math methods, refactors and specs (thanks @scidom).
Inheriting generic classes is now possible.
Creating arrays of generic types (i.e.: [] of Thread) is now possible.
Allow using an alias in a block type (i.e.: alias F = Int32 ->, &block : F).
json_mapping macro supports a simpler syntax: json_mapping({key1: Type1, key2: Type2}).
Spec: added be_a(type) matcher.
Spec: added be > ... and similar matchers for >=, < and <=.
Added File::file? and File::directory?.
CSV parser can parse from String or IO.
When invoking the compiler like this: crystal foo.cr -o foo the build command is assumed instead of run.
Added short symbol notation for methods that are operators (i.e. :+, :*, :[], etc.).
Added TimeSpan#ago, TimeSpan#from_now, MonthSpan#ago and MonthSpan#from_now.

0.5.3 (2014-11-06)

Spec: when a should or should_not fail, the filename and line number, including the source's line, is included in the error message.
Spec: added -l switch to be able to run a spec defined in a line.
Added crystal spec file:line
Properties (property, setter, getter) can now be restricted to a type with the syntax property name :: Type.
Enums can be used outside lib. They inherit Enum, can have methods and can be marked with @[Flags].
Removed the distinction between lib enums and regular enums.
Fixed: it was incorrectly possible to define class, def, etc. inside a call block.
The syntax for specifying the base type of an enum, enum Name < BaseType has been deprecated. Use enum Name : BaseType.
Added Array#<=> and make it comparable to other arrays.

0.5.2 (2014-11-04)

New command line interface to the compiler (crystal build ..., crystal run ..., crystal spec, etc.). The default is to compiler and run a program.
crystal eval without arguments reads from standard input.
Added preliminar crystal deps command.
__FILE__, __DIR__ and __LINE__, when used as def default arguments, resolve to the caller location (similar to D and Swift)
Allow as to determine a type even if the casted value doesn't have a type yet.
Added is_a? in macros. The check is against an AST node name. For example node.is_a?(HashLiteral).
Added emit_null property to json_mapping.
Added converter property to json_mapping.
Added pp in macros.
Added to_pretty_json.
Added really basic CSV.parse.
Added Regex.escape.
Added String#scan.
Added -e switch to spec, to run specs that match a pattern.
Added --fail-fast swtich to spec.
Added HTTPClient#basic_auth.
Added DeclareVar, Def and Arg macro methods.
Added Time and TimeSpan structs. TimeWithZone will come later.
Added Array#fill (thanks @Exilor).
Added Array#uniq.
Optimized File.read_lines.
Allow any expression inside {% ... %} so that you can interpret code without outputting the result.
Allow \ at the end of a line.
Allow using if and unless inside macro expressions.
Allow marking a fun/def as @[Raises] (useful when a function can potentially raise from a callback).
Allow procs are now considered @[Raises].
OAuth2::Client supports getting an access token via authorization code or refresh token.
Consecutive string literals are automatically concatenated by the parser as long as there is a \ with a newline between them.
Many bug fixes.

0.5.1 (2014-10-16)

Added json_mapping macro.
Added Signal module.
Added Tempfile class.
Enhanced HTTP::Client.
Added OAuth::Consumer.
Added OAuth2::Client.
Added OpenSSL::HMAC.
Added SecureRandom.
New syntax for array/hash-like classes. For example: Set {1, 2, 3} and HTTP::Headers {"content-type": "text/plain"}. These just create the type and use << or []=.
Optimized Json parsing performance.
Added a CSV builder.
XML reader can parse from an IO.
Added Dir::glob and Dir::Entries (thanks @jhass)
Allow ensure as an expression suffix.
Fixed #219: Proc type is not inferred when passing to library fun and the return type doesn't match.
Fixed #224: Class#new doesn't pass a block.
Fixed #225: ICE when comparing void to something.
Fixed #227: Nested captured block looses scope and crashes compiler.
Fixed #228: Macro expansion doesn't retain symbol escaping as needed.
Fixed #229: Can't change block context if defined within module context.
Fixed #230: Type interference breaks equality operator.
Fixed #233: Incorrect no block given message with new.
Other bug fixes.

0.5.0 (2014-09-24)

String overhaul, and optimizations

0.4.5 (2014-09-24)

Define backtick (`) for command execution.
Allow string literals as keys in hash literals: {"foo": "bar"} # :: Hash(String, String)
Allow ifdef as a suffix.
Integer division by zero raises a DivisionByZero exception.
Link attributes are now only processed if a lib function is used.
Removed the type Name : Type syntax (use type Name = Type instead).
Removed the lib Lib("libname"); end syntax. Use @[Link] attribute instead.
Fixed some require issues.
String representation includes length.
Upgraded to LLVM 3.5.

0.4.4 (2014-09-17)

Fixed #193: allow initializing an enum value with another's one.
The record macro is now variadic, so instead of record Vec3, [x, y, z] write record Vec3, x, y, z.
The def_equals, def_hash and def_equals_and_hash macros are now variadic.
The property, getter and setter macros are now variadic.
All String methods are now UTF-8 aware.
String#length returns the number of characters, while String#bytesize return the number of bytes (previously length returned the number of bytes and bytesize didn't exist).
String#[](index) now returns a Char instead of an UInt8, where index is counted in characters. There's also String#byte_at(index).
Removed the \x escape sequence in char and string literals. Use \u instead.
initialize methods are now protected.
Added IO#gets_to_end.
Added backticks (...) and %x(...) for command execution.
Added %r(...) for regular expression literals.
Allow interpolations in regular expresion literals.
Compiling with --release sets a release flag that you can test with ifdef.
Allow passing splats to C functions
A C type can now be declared like type Name = Type (type Name : Type will be deprecated).
Now a C struct/union type can be created with named arguments.
New attributes syntax: @[Attr(...)] instead of @:Attr. The old syntax will be deprecated in a future release.
New link syntax for C libs: @[Link("name")] (uses name as pkg-config name if available or -lname instead), @[Link(ldflags: "...")] to pass raw flags to the linker, @[Link("name", static: true)] to try to find a static library first, and @[Link(framework: "AppKit")] (for Mac OSX).
Added an exec method to execute shell commands. Added the system and backtick similar to Ruby ones.
Added be_truthy and be_falsey spec matchers. Added Array#zip without a block. (thanks @mjgpy3)
Added getter? and property? macros to create methods that end with ?.
Added a CGI module.
The compiler now only depends on cc for compiling (removed dependency to llc, opt, llvm-dis and clang).
Added IO#tty?.
Some bug fixes.

0.4.3 (2014-08-14)

Reverted a commit that introduced random crashes.

0.4.2 (2014-08-13)

Fixed #187: mixing yield and block.call crashes the compiler.
Added \u unicode escape sequences inside strings and chars (similar to Ruby). \x will be deprecated as it can generate strings with invalid UTF-8 byte sequences.
Added String#chars.
Fixed: splats weren't working in initialize.
Added the private and protected visibility modifiers, with the same semantics as Ruby. The difference is that you must place them before a def or a macro call.
Some bug fixes.

0.4.1 (2014-08-09)

Fixed #185: -e flag stopped working.
Added a @length compile-time variable available inside tuples that allows to do loop unrolling.
Some bug fixes.

0.4.0 (2014-08-08)

Support splats in macros.
Support splats in defs and calls.
Added named arguments.
Renamed the make_named_tuple macro to record.
Added def_equals, def_hash and def_equals_and_hash macros to generate them from a list of fields.
Added Slice(T), which is a struct having a pointer and a length. Use this in IO for a safe API.
Some StaticArray fixes and enhancements.

0.3.5 (2014-07-29)

(breaking change) Removed the special -> operator for pointers of structs/unions: instead of foo->bar use foo.value.bar; instead of foo->bar = 1 use foo.value.bar = 1.
Added colorize file that provides methods to easily output bash colors.
Now you can use modules as generic type arguments (for example, do x = [] of IO).
Added SSL sockets. Now HTTP::Server implements HTTPS.
Macros have access to constants and types.
Allow iterating a range in macros with for.
Use cpu cycle counter to initialize random.
method_missing now works in generic types.
Fixed #154: bug, constants are initialized before global variables.
Fixed #168: incorrect type inference of instance variables if not assigned in superclass.
Fixed #169: responds_to? wasn't working with generic types.
Fixed #171: ensure blocks are not executed if the rescue block returns from a def.
Fixed #175: invalid code generated when using with/yield with structs.
Fixed some parser issues and other small issues.
Allow forward struct/union declarations in libs.
Added String#replace(Regex, String)
Added a Box(T) class, useful for boxing value types to pass them to C as Void*.

0.3.4 (2014-07-21)

Fixed #165: restrictions with generic types didn't work for hierarchy types.
Allow using a single underscore in restrictions, useful for matching against an n-tuple or an n-function where you don't care about the types (e.g.: def foo(x : {_, _}).
Added a generate_hash macro that generates a hash methods based on some AST nodes.
Added very basic previous_def: similar to super, but uses the previous definition of a method. Useful to decorate existing methods (similar to alias_method_chain). For now the method's type restrictions must match for a previous definition to be found.
Made the compiler a bit faster
Added env in macros, to fetch an environment value. Returns a StringLiteral if found or NilLiteral if not.
Make return 1, 2 be the same as return {1, 2}. Same goes with break and next.
Added Pointer#as_enumerable(size : Int) to create an Enumerable from a Pointer with an associated size, with zero overhead. Some methods removed from Pointer: each, map, to_a, index.
Added StaticArray::new, StaticArray::new(value), StaticArray::new(&block), StaticArray#shuffle! and StaticArray#map!.
Faster Char#to_s(io : IO)

0.3.3 (2014-07-14)

Allow implicit conversion to C types by defining a to_unsafe method. This removed the hardcoded rule for converting a String to UInt8* and also allows passing an Array(T) to an argument expecting Pointer(T).
Fixed .is_a?(Class) not working (#162)
Attributes are now associated to AST nodes in the semantic pass, not during parsing. This allows macros to generate attributes that will be attached to subsequent expressions.
(breaking change) Make ENV#[] raise on missing key, and added ENV#[]?
(breaking change) Macro defs are now written like macro def name(args) : ReturnType instead of def name(args) : ReturnType, which was a bit confusing.

0.3.2 (2014-07-10)

Integer literals without a suffix are inferred to be Int32, Int64 or UInt64 depending on their value.
Check that integer literals fit into their types.
Put back Int#to_s(radix : Int) (was renamed to to_s_in_base in the previous release) by also specifying a restriction in Int#to_s(io : IO).
Added expect_raises macros in specs

0.3.1 (2014-07-09)

(breaking change) Replaced @name inside macros with @class_name.
(breaking change) Instance variables inside macros now don't have the @ symbols in their names.

0.3.0 (2014-07-08)

Added Array#each_index
Optimized String#* for the case when the string has length one.
Use GC.malloc_atomic for String and String::Buffer (as they don't contain internal pointers.)
Added a PointerAppender struct to easily append to a Pointer while counting at the same time (thanks @kostya for the idea).
Added a Base64 module (thanks @kostya)
Allow default arguments in macros
Allow invoking new on a function type. For example: alias F = Int32 -> Int32; f = F.new { |x| x + 1 }; f.call(2) #=> 3.
Allow omitting function argument types when invoking C functions that accept functions as arguments.
Renamed @name to @class_name inside macros. @name will be deprecated in the next version.
Added IO#read_fully
Macro hooks: inherited, included and extended
method_missing macro
Added {{ raise ... }} inside macros to issue a compile error.
Started JSON serialization and deserialization
Now at_exit handlers are run when you invoke exit
Methods can be marked as abstract
New convention for to_s and inspect: you must override them receiving an IO object
StringBuilder and StringBuffer have been replaced by StringIO

0.2.0 (2014-06-24)

Removed icr (a REPL): it is abandoned for the moment because it was done in a hacky, non-reliable way
Added very basic String#underscore and String#camelcase.
The parser generates string literals out of strings with interpolated string literals. For example, "#{__DIR__}/foo" is interpolated at compile time and generates a string literal with the full path, since __DIR__ is just a (special) string literal.
(breaking change) Now macro nodes are always pasted as is. If you want to generate an id use {{var.id}}.

Previously, a code like this:
```
macro foo(name)
  def {{name}}; end
end

foo :hello
foo "hello"
foo hello
```
generated this:
```
def hello; end
def hello; end
def hello; end
```
With this change, it generates this:
```
def :hello; end
def "hello"; end
def hello; end
```
Now, to get an identifier out of a symbol literal, string literal or a name, use id:
```
macro foo(name)
  def {{name.id}}; end
end
```
Although it's longer to type, the implicit "id" call was sometimes confusing. Explicit is better than implicit.

Invoking id on any other kind of node has no effect on the pasted result.
Allow escaping curly braces inside macros with \{. This allows defining macros that, when expanded, can contain other macro expressions.
Added a special comment-like pragma to change the lexer's filename, line number and column number.
```
# foo.cr
a = 1
#<loc:"bar.cr",12,24>b = 2
c = 3
```
In the previous example, b = 2 (and the rest of the file) is considered as being parsed from file bar.cr at line 12, column 24.
Added a special run call inside macros. This compiles and executes another Crystal program and pastes its output into the current program.

As an example, consider this program:
```
# foo.cr
{{ run("my_program", 1, 2, 3) }}
```
Compiling foo.cr will, at compile-time, compile my_program.cr and execute it with arguments 1 2 3. The output of that execution is pasted into foo.cr at that location.

Added ECR (Embedded Crystal) support. This is implemented using the special run macro call.

A small example:

# template.ecr
Hello <%= @msg %>

# foo.cr
require "ecr/macros"

class HelloView
  def initialize(@msg)
  end

  # This generates a to_s method with the contents of template.ecr
  ecr_file "template.ecr"
end

view = HelloView.new "world!"
view.to_s #=> "Hello world!"

The nice thing about this is that, using the #<loc...> pragma for specifying the lexer's location, if you have a syntax/semantic error in the template the error points to the template :-)

0.1.0 (2014-06-18)

First official release

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0.29.0 (2019-06-05)

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0.27.1 (2019-01-30)

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0.27.0 (2018-11-01)

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