ch13.adoc

13 Building projects in Haskell

Files at https://github.com/lukleh/haskell-book-exercises/tree/gh-pages/ch13

https://github.com/commercialhaskell/stack/blob/master/doc/faq.md

https://github.com/commercialhaskell/stack/blob/master/doc/GUIDE.md

http://docs.haskellstack.org/en/stable/README.html

Differences between cabal and stack

1. stack new proj instead of mkdir proj; cd proj; cabal init

2. stack creates Lib automatically

3. cabal sandbox init no need

4. stack build

5. stack exec proj-exe

6. stack ghci or stack repl - they appear to be identical

13.3 Working with a basic project

All the changes over the whole chapter at https://github.com/lukleh/haskell-book-exercises/tree/gh-pages/ch13/hello

13.7 More on importing modules

Intermission: Check your understanding

1. forever and when

2. all the import without qualified keyword

3. everything exported in Database.Blacktip.Types

4. details

   1. just look for what is after the as keyword in the imports

   2. Filesystem

   3. Control.Monad

13.9 do syntax and IO

1. error as expected

   link:ch13_13.9_0.hs[role=include]

2. consumes two characters and prints True or False

   link:ch13_13.9_1.hs[role=include]

3. consumes two characters and prints True if true, or nothing.

   link:ch13_13.9_2.hs[role=include]

13.15 Chapter exercises

Hangman game logic

Sources at https://github.com/lukleh/haskell-book-exercises/tree/gh-pages/ch13/hangman

To count only incorrect guesses, I have modified gameOver condition to if (length guessed - length (filter isJust discovered)) > 7 then

Modifying code

1. Caesar and Vigenere cyphers taking input from user

   link:ch13_13.15_1.hs[role=include]

   link:ch13_13.15_0.hs[role=include]

2. using exitSuccess in palindrome

   link:ch13_13.15_2.hs[role=include]

3. palindrome on sentences

   Warning

   not sure I get the assignment other than using toLower

   link:ch13_13.15_3.hs[role=include]

4. gimmePerson

   link:ch13_13.15_4.hs[role=include]