Macros called with parens can have arguments parsed as keywords

[timholy]

Not sure whether this is intended, but it did surprise me:

macro showheads(arg1, arg2)
    @show arg1.head
    @show arg2.head
    :nothing
end

julia> @showheads (1,2) (x = 5)
arg1.head => :tuple
arg2.head => :(=)

julia> @showheads((1,2), (x = 5))
arg1.head => :tuple
arg2.head => :kw

Using 0.3.0-rc1.

[StefanKarpinski]

Ah, that's an interesting corner case. The macro parser with parens just reuses the function call parsing logic, which has occasionally caused some issues like this.

[jakebolewski]

Yeah we probably need a macro parsing context to resolve Function / macro differences.

[JeffBezanson]

I don't think it's super surprising that this parses like a function call.

[timholy]

It's not super-surprising, but I think there's a temptation to think of @cmd a b and @cmd(a,b) as meaning the same thing.

[tpapp]

I recently ran into this, trying to implement someting like the CL macro

(defmacro invisible (&body body)
  `(progn ,@body (values))

in Julia as

macro invisible(expressions...)
  quote
    $(expressions...)
    nothing
  end
end

and got

julia> @invisible a=1
julia> @invisible(a=1)
ERROR: unsupported or misplaced expression kw

It would be great if the two forms parsed the same way.

[Tetralux]

Ref #12021;
@foo((1,2), (x = 5)) and @foo (1,2) (x = 5) should both pass (1, 2) and :(x = 5) to the macro.