Using julia keywords as type fields

[domluna]

This is a corner case but it can come up when you're generating code from a language that's end not Julia, such as GraphQL and a field is called "end".

julia> JLKwStruct(;name=:ABC, fields = [JLKwField(name=:end)])
begin
    #= /home/dom/.julia/packages/Expronicon/trhCs/src/codegen.jl:101 =#
    struct ABC
        end
    end
    #= /home/dom/.julia/packages/Expronicon/trhCs/src/codegen.jl:102 =#
    begin
        #= /home/dom/.julia/packages/Expronicon/trhCs/src/codegen.jl:156 =#
        function ABC(; end)
            ABC(end)
        end
        #= /home/dom/.julia/packages/Expronicon/trhCs/src/codegen.jl:157 =#
        nothing
    end
end

This will be unable to be parsed but it can work if we replace uses of end with the following:

julia> JLKwStruct(;name=:ABC, fields = [JLKwField(name=:end)])
begin
    #= /home/dom/.julia/packages/Expronicon/trhCs/src/codegen.jl:101 =#
    struct ABC
        var"end"
    end
    #= /home/dom/.julia/packages/Expronicon/trhCs/src/codegen.jl:102 =#
    begin
        #= /home/dom/.julia/packages/Expronicon/trhCs/src/codegen.jl:156 =#
        function ABC(; var"end")
            ABC(var"end")
        end
        #= /home/dom/.julia/packages/Expronicon/trhCs/src/codegen.jl:157 =#
        nothing
    end
end

so I guess the idea is to detect Julia keywords and wrap them with @var_str.

It doesn't look like this can be done on input but maybe during codegen?

[domluna]

actually this would be done during printing not codegen

[Roger-luo]

I think our current printing is not always correct since it kinda just manually handles the expression heads in a @switch stmts instead from a legit parser.

And I think the above is correct because you can just do the same thing in Julia Expr, e.g

julia> print(ex)
struct Foo
    #= REPL[7]:2 =#
    end
end
julia> dump(ex)
Expr
  head: Symbol struct
  args: Array{Any}((3,))
    1: Bool false
    2: Symbol Foo
    3: Expr
      head: Symbol block
      args: Array{Any}((2,))
        1: LineNumberNode
          line: Int64 2
          file: Symbol REPL[7]
        2: Symbol end

and

julia> :(struct Foo; var"end" end)
:(struct Foo
      #= REPL[20]:1 =#
      end
  end)

So what is missing is actually a validator of Julia AST, if we hope to have something that works less specifically, which can be very hard since there hasn't been any form of formal definition of Julia grammar...

so what I can think of at the moment is a simpler validator that checks Julia keyword and error when user creating things like JLField/JLKwField

[Roger-luo]

Ah I think I misinterpreted your point, yeah the printing is wrong, it should be var"end", would need to handle this as a specific case for Symbol: https://github.com/Roger-luo/Expronicon.jl/blob/master/src/printing.jl#L314

[domluna]

it’s pretty tricky though since you only want to do this for certain cases and also have it propagate throughout the function body for functions as well.

For my specific case i’m adding an underscore to the front and then adding this case to generated get/set property functions. GraphQL doesn’t allow underscore in the front of names so this works out

On Tuesday, March 29, 2022, Rogerluo @.***> wrote:

Ah I think I misinterpreted your point, yeah the printing is wrong, it should be var"end", would need to handle this as a specific case for Symbol: https://github.com/Roger-luo/Expronicon.jl/blob/master/src/ printing.jl#L314

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[Roger-luo]

I think for keyword we can just print them as var? Since they won't appear in the args field of expressions anyway