julia> module X
export f
function f(x)
g(x)
end
end
X
julia> module Y
using X
g(x) = 2x
f(4)
end
ERROR: UndefVarError: g not defined
in f at ./none:4
I am trying to use another function g(x) which can be defined in any other
module by calling function f.
This is the idea at its simplest. But It seems it doesn't work.
On Monday, February 15, 2016 at 7:03:54 PM UTC-8, Cedric St-Jean wrote:
>
> Hi Julia, what are you trying to achieve, concretely?
>
> On Monday, February 15, 2016 at 2:36:15 PM UTC-5, Julia Tylors wrote:
>>
>> I started to think, this may be normal working of julia.
>>
>> import X:_ex_func
>> using X
>> _ex_func() = println("DDD")
>> _1ex_func()
>> julia> _1ex_func()
>> DDD
>> sty
>>
>> julia> module Y
>> using X
>> _
>> _1ex_func __precompile__ _ex_func
>> julia> module Y
>> using X
>> _1ex_func()
>> end
>> DDD
>> sty
>> Y
>>
>> However, it seems once a function is overridden, it stays overridden in
>> every module.
>> That is a very weird idea. why is there such a design decision? Can
>> someone care to explain it?
>>
>> Thanks
>>
>> On Monday, February 15, 2016 at 11:04:07 AM UTC-8, Julia Tylors wrote:
>>>
>>> Guys, this is no solution to my problem,
>>>
>>> escaping basically tells the the quoted expr to be resolved outside the
>>> macro as Lutfullah did. However in my case, escaping a function call
>>> doesn't work for some reason.
>>> And for that matter, esc should be recursive though...
>>>
>>>
>>> On Monday, February 15, 2016 at 6:44:58 AM UTC-8, Joshua Ballanco wrote:
>>>>
>>>> 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
>>>>
>>>
