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digitalmars.D - How to write template ModuleOf!T ?

reply kenji hara <k.hara.pg gmail.com> writes:
Hello, all.

I tried to ModuleOf!T in some day. It may works like this:
----
module mod.a;
struct S{}
struct Nest{
  struct S{}
}

module test;
import mod.a;
static assert(ModuleOf!(S) == "mod.a");
static assert(ModuleOf!(Nest.S) == "mod.a");
----
Partially I succeed to get module name of mod.a.S by using .mangeof property.
But sadly failed to get of mod.a.Nest.S.
I think that D should support __traits(isModuleName, ModuleName).

Do you think?

P.S.
The original motivation is reproduction ADL in C++.
Currently in D, we cannot call function f specialized by S in following code:
----
module a;
struct S{...}
void f(S s){...}  // specialized implementation

module b;
void f(T)(T t){...}  // generic implementation
void someAlgorithm(T)(T t){
  f(t)
}
----
module test;
import a, b;
void main(){
  S s;
  someAlgrithm(s);
}
----

But, if ModuleOf exists, we can call specialized f to write
someAlgorithm as follows:
----
template ScopeOf(T)
{
  mixin("import ScopeOf = " ~ ModuleOf!T ~ ";");
}
void someAlgorithm(T)(T t){
  static if (is(typeof(ScopeOf!T.f)))
    alias ScopeOf!T.f f;
  else
    alias .f f;
  f(s);  // call function specialized by T or generic one.
}
----

This is like ADL in C++, but has no implicit problem.
Thanks for your reading.

Kneji
Dec 15 2010
next sibling parent "Simen kjaeraas" <simen.kjaras gmail.com> writes:
kenji hara <k.hara.pg gmail.com> wrote:

 I think that D should support __traits(isModuleName, ModuleName).

 Do you think?

A way to traverse the hierarchy of identifiers would be nice. There is currently no way to identify an identifier as a template or module. I would say is( T == module ) and is( T == template ) is the way to go, but I'm not entirely sure (they're not types, which is what is() deals in). -- Simen
Dec 15 2010
prev sibling parent kenji hara <k.hara.pg gmail.com> writes:
2010/12/15 Simen kjaeraas <simen.kjaras gmail.com>:
 kenji hara <k.hara.pg gmail.com> wrote:

 I think that D should support __traits(isModuleName, ModuleName).

 Do you think?

A way to traverse the hierarchy of identifiers would be nice. There is currently no way to identify an identifier as a template or module. I would say is( T == module ) and is( T == template ) is the way to go, but I'm not entirely sure (they're not types, which is what is() deals in). -- Simen

Even if we can use is(T == module), T should be valid identifier. Then, we should treat the module name yet not imported as a string. Therefore, Is-expression will not fit this. Thanks.
Dec 15 2010