On February 14, 2016 at 21:49:30, Julia Tylors
([email protected](mailto:[email protected])) wrote:
> Hi fellows,
>
>
> I was coding a macro, and I am having a prefix issue with functions.
>
> basically the problem is: Every single one of available functions (_ex_func)
> which i want to be globally accessible are prefixed with the name of the
> module(X) in which the macro f is defined
>
>
> Here is the code example:
>
> julia> module X
> export @f
> macro f(x)
> st = string("_",x)
> sy = symbol(st)
> esc(quote
> function ($sy)()
> println("st")
> end
>
> function ($(symbol(string("_1",x))))()
> ($sy)()
> println("sty")
> end
> export $sy
> export $(symbol(string("_1",x)))
> end
> )
> end
> @eval @f ex_func
> end
> X
>
> julia> using X
>
> julia> _
>
> _1ex_func __precompile__ _ex_func
> julia> _1ex_func.env.defs.func.code
> AST(:($(Expr(:lambda, Any[], Any[Any[],Any[],0,Any[]], :(begin # none, line
> 12:
> (X._ex_func)() # none, line 13: # i want this to be not prefixed by X
> return (X.println)("sty")
> end)))))
>
> julia> macroexpand(:(@f ex_func))
> quote # none, line 7:
> function _ex_func() # none, line 8:
> println("st")
> end # none, line 11:
> function _1ex_func() # none, line 12:
> _ex_func() # none, line 13: # it seems OK, here!!!
> println("sty")
> end # none, line 15:
> export _ex_func # none, line 16:
> export _1ex_func
> end
>
>
>
> as you may see , I may well define _ex_func in other modules and use it from
> the function X._1ex_func().
> But this prevents me doing it.
>
> How can i solve this problem?
>
> Thanks
OH! I know this!
Actually, I do believe this is a bug in macro hygiene and have been meaning to
file it. In the mean time, double-escaping should work for you:
julia> module X
macro p(y)
quote
println($y)
end
end
macro q(y)
quote
println(:($($y)))
end
end
end
X
julia> using X
julia> test = "Hello, world"
"Hello, world"
julia> @X.p(test)
ERROR: UndefVarError: test not defined
julia> @X.q(test)
Hello, world
