I don't think that the `using X` inside module Y here re-runs the eval,
there is only one instance of modules, it doesn't create a new instance
inside module Y. So your replacement of X._ex_func() at top level still
holds.
On Tuesday, February 16, 2016 at 5:36:15 AM UTC+10, 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
>>>
>>
