Parentheses not required warning in using A: (..)

[LilithHafner]

In this case, parentheses are requires, but the warning says they are not:

julia> JuliaSyntax.parse(Expr, "using A: (..)")
ERROR: ParseError:
# Warning @ line 1:10
using A: (..)
#        └──┘ ── parentheses are not required here
Stacktrace:
 [1] _parse(rule::Symbol, need_eof::Bool, ::Type{…}, text::String, index::Int64; version::VersionNumber, ignore_trivia::Bool, filename::Nothing, first_line::Int64, ignore_errors::Bool, ignore_warnings::Bool, kws::@Kwargs{})
   @ JuliaSyntax ~/.julia/dev/JuliaSyntax/src/parser_api.jl:93
 [2] _parse (repeats 2 times)
   @ JuliaSyntax ~/.julia/dev/JuliaSyntax/src/parser_api.jl:77 [inlined]
 [3] parsestmt(::Type{Expr}, text::String)
   @ JuliaSyntax ~/.julia/dev/JuliaSyntax/src/parser_api.jl:140
 [4] parse(::Type, ::Vararg{Any}; kwargs::@Kwargs{})
   @ JuliaSyntax ./deprecated.jl:116
 [5] parse(::Type, ::Vararg{Any})
   @ JuliaSyntax ./deprecated.jl:113
 [6] top-level scope
   @ REPL[19]:1
Some type information was truncated. Use `show(err)` to see complete types.

julia> JuliaSyntax.parse(Expr, "using A: ..")
ERROR: ParseError:
# Error @ line 1:12
using A: ..
#          └ ── premature end of input
Stacktrace:
 [1] _parse(rule::Symbol, need_eof::Bool, ::Type{…}, text::String, index::Int64; version::VersionNumber, ignore_trivia::Bool, filename::Nothing, first_line::Int64, ignore_errors::Bool, ignore_warnings::Bool, kws::@Kwargs{})
   @ JuliaSyntax ~/.julia/dev/JuliaSyntax/src/parser_api.jl:93
 [2] _parse (repeats 2 times)
   @ JuliaSyntax ~/.julia/dev/JuliaSyntax/src/parser_api.jl:77 [inlined]
 [3] parsestmt(::Type{Expr}, text::String)
   @ JuliaSyntax ~/.julia/dev/JuliaSyntax/src/parser_api.jl:140
 [4] parse(::Type, ::Vararg{Any}; kwargs::@Kwargs{})
   @ JuliaSyntax ./deprecated.jl:116
 [5] parse(::Type, ::Vararg{Any})
   @ JuliaSyntax ./deprecated.jl:113
 [6] top-level scope
   @ REPL[20]:1
Some type information was truncated. Use `show(err)` to see complete types.

[c42f]

Ah this is unfortunate. I really wanted to eventually deprecate allowing parentheses in using (arguably the reference parser allows parens in many places where they add visual noise).

We do have some icky inconsistent syntax for dealing with these kind of things. For example:

julia> module A
           .. = 1
       end

There's various inconsistent forms which allow importing .. from A:

julia> import .A.(..)

julia> import .A.var".."

julia> import .A.:(..)

Only some of which are consistent with accessing a field of A

julia> A.:(..)
1

julia> A.var".."
1

# A dotcall instead :(
julia> A.(..)
ERROR: MethodError: objects of type Module are not callable

I'm quite tempted to say that the long game is "just use var for this" and to really deprecate parentheses in these cases. Because var syntax is a completely general way to construct identifiers regardless of whether they're keywords or other special syntax which can't be parenthesized.

[ericphanson]

Is there a workaround that doesn't involve changing the source code? I again want to parse Makie (this time for ExplicitImports.jl) and cannot :(.

Also, why does the Base version work? E.g. I can load Makie on Julia v1.10. Is it that it falls back to the flisp parser?

edit: fyi SparseArrays also hits this

[ericphanson]

Is there a workaround that doesn't involve changing the source code?

There is! It turns out this is a "warning" (despite only using the word "error" in the message), so ignore_warnings=true works:

julia> JuliaSyntax.parseall(JuliaSyntax.GreenNode, "import Makie: (..)")
ERROR: ParseError:
# Warning @ line 1:15
import Makie: (..)
#             └──┘ ── parentheses are not required here
Stacktrace:
 [1] _parse(rule::Symbol, need_eof::Bool, ::Type{…}, text::String, index::Int64; version::VersionNumber, ignore_trivia::Bool, filename::Nothing, first_line::Int64, ignore_errors::Bool, ignore_warnings::Bool, kws::@Kwargs{})
   @ JuliaSyntax ~/.julia/packages/JuliaSyntax/eqCSU/src/parser_api.jl:93
 [2] _parse (repeats 2 times)
   @ ~/.julia/packages/JuliaSyntax/eqCSU/src/parser_api.jl:77 [inlined]
 [3] parseall(::Type{JuliaSyntax.GreenNode}, text::String)
   @ JuliaSyntax ~/.julia/packages/JuliaSyntax/eqCSU/src/parser_api.jl:143
 [4] top-level scope
   @ REPL[18]:1
Some type information was truncated. Use `show(err)` to see complete types.

julia> JuliaSyntax.parseall(JuliaSyntax.GreenNode, "import Makie: (..)", ignore_warnings=true)
     1:18     │[toplevel]
     1:18     │  [import]
     1:18     │    [:]
     1:6      │      import
     7:12     │      [importpath]
     7:7      │        Whitespace
     8:12     │        Identifier       ✔
    13:13     │      :
    14:18     │      [importpath]
    14:14     │        Whitespace
    15:18     │        [parens]
    15:15     │          (
    16:17     │          ..             ✔
    18:18     │          )

[LilithHafner]

why does the Base version work?

Base uses ignore_warnings=true

[ericphanson]

It turns out this is a "warning" (despite only using the word "error" in the message)

My apologies, this is wrong, it does say warning! It is just very light and I missed it.

[c42f]

Is .. the only thing where parens are really required?