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digitalmars.D - template mixin function name mangling

reply "John Colvin" <john.loughran.colvin gmail.com> writes:
Apologies for another question so short after the previous one.

tempmix.d:

mixin template Foo()
{
     extern(C) void foo() {}
}

mixin Foo!();

extern(C) void bar() {}


$dmd -c tempmix.d
$nm tempmix.o
0000000000000000 t
0000000000000000 T bar
0000000000000000 D _D7tempmix12__ModuleInfoZ
0000000000000000 T _D7tempmix15__unittest_failFiZv
0000000000000000 T _D7tempmix7__arrayZ
0000000000000000 T _D7tempmix8__assertFiZv
0000000000000000 W _D7tempmix8__T3FooZ3fooUZv
                  U _d_array_bounds
                  U _d_assertm
                  w _d_dso_registry
                  U _Dmodule_ref
                  U _d_unittestm

foo gets mangled D-style, bar is left bare. Is this deliberate? I 
was under the impression that they should both be left bare.

I tried moving the extern(C) around to various other places, 
including extern(C): at the top of the file. No success.
Apr 21 2013
parent reply "Peter Alexander" <peter.alexander.au gmail.com> writes:
On Sunday, 21 April 2013 at 21:43:03 UTC, John Colvin wrote:

 Apologies for another question so short after the previous one.

 tempmix.d:

 mixin template Foo()
 {
     extern(C) void foo() {}
 }

 mixin Foo!();

 extern(C) void bar() {}


 $dmd -c tempmix.d
 $nm tempmix.o
 0000000000000000 t
 0000000000000000 T bar
 0000000000000000 D _D7tempmix12__ModuleInfoZ
 0000000000000000 T _D7tempmix15__unittest_failFiZv
 0000000000000000 T _D7tempmix7__arrayZ
 0000000000000000 T _D7tempmix8__assertFiZv
 0000000000000000 W _D7tempmix8__T3FooZ3fooUZv
                  U _d_array_bounds
                  U _d_assertm
                  w _d_dso_registry
                  U _Dmodule_ref
                  U _d_unittestm

 foo gets mangled D-style, bar is left bare. Is this deliberate? 
 I was under the impression that they should both be left bare.

 I tried moving the extern(C) around to various other places, 
 including extern(C): at the top of the file. No success.


Hmmm, not sure what should happen here. Seems to be an 
underspecified part of the language.

On a first glance, it would appear as a bug. foo should be mixed 
in as extern(C), just as if you had copied it there by hand, but 
problems arise with situations like this:

mixin template A() {
     extern(C) int foo() { return 1; }
}

mixin template B() {
     extern(C) int foo() { return 2; }
}

mixin A();
mixin B();

void main() {
     int x = A.foo() + B.foo();
}

If both foo's have the same symbol, then how am I able to 
disambiguate them in code?

Maybe duplicate extern(C) template mixin symbols need to be an 
error?
Apr 22 2013
next sibling parent "Peter Alexander" <peter.alexander.au gmail.com> writes:
On Monday, 22 April 2013 at 09:03:24 UTC, Peter Alexander wrote:

 mixin A();
 mixin B();

 void main() {
     int x = A.foo() + B.foo();
 }


Oops, syntax fail. Should be something more like this:

mixin A a;
mixin B b;

void main() {
     int x = a.foo() + b.foo();
}
Apr 22 2013
prev sibling parent "John Colvin" <john.loughran.colvin gmail.com> writes:
On Monday, 22 April 2013 at 09:03:24 UTC, Peter Alexander wrote:

 mixin template A() {
     extern(C) int foo() { return 1; }
 }

 mixin template B() {
     extern(C) int foo() { return 2; }
 }

 mixin A a;
 mixin B b;

 void main() {
     int x = a.foo() + b.foo();
 }

 If both foo's have the same symbol, then how am I able to 
 disambiguate them in code?

 Maybe duplicate extern(C) template mixin symbols need to be an 
 error?


If there are true duplicates then it would need to be an error. 
However, if a mixin uses a mixin identifier then it's going to 
need to be mangled anyway, so only

mixin A;
mixin B;

would have to be an error. It already is an error, but 
unfortunately only when you reference the content of the mixin, 
not at the mixin statement.
Apr 22 2013