Why doesn't this work:

# template MFoo(T)
# {
# 	T foo(T a)
# 	{
# 		return a;
# 	}
# }
#
# class Foo
# {
# 	mixin MFoo!(int);
# 	mixin MFoo!(int*);
# }
#
# void main()
# {
# 	Foo f = new Foo;
# 	f.foo(2);
# }

Error:
"console_main.d(3): function console_main.Foo.MFoo!(int) MFoo_i.foo conflicts with console_main.Foo.MFoo!(int*) MFoo_Pi.foo at console_main.d(3)"


On the other hand, this code is just fine:

# class Foo
# {
# 	int foo(int a)
# 	{
# 		return a;
# 	}
#
# 	int* foo(int* a)
# 	{
# 		return a;
# 	}
# }
#
# void main()
# {
# 	Foo f = new Foo;
# 	f.foo(2);
# }


Am I missing/mixing something about mixins ? I'd really like the mixin code to work... right now I have to make huge cut'n'pasting in my project :(


-- 
Tomasz Stachowiak  /+ a.k.a. h3r3tic +/

See if this works:

# class Foo
# {
# 	mixin MFoo!(int) MFooMix1;
#       alias MFooMix.foo foo;
# 	mixin MFoo!(int*) MFooMix2;
#       alias MFooMix.foo foo;
# }

On Fri, 06 May 2005 19:04:31 +0200, Tom S wrote:

> Why doesn't this work:
> 
> # template MFoo(T)
> # {
> # 	T foo(T a)
> # 	{
> # 		return a;
> # 	}
> # }
> #
> # class Foo
> # {
> # 	mixin MFoo!(int);
> # 	mixin MFoo!(int*);
> # }
> #
> # void main()
> # {
> # 	Foo f = new Foo;
> # 	f.foo(2);
> # }
> 
> Error:
> "console_main.d(3): function console_main.Foo.MFoo!(int) MFoo_i.foo
> conflicts with console_main.Foo.MFoo!(int*) MFoo_Pi.foo at
> console_main.d(3)"
> 
> 
> On the other hand, this code is just fine:
> 
> # class Foo
> # {
> # 	int foo(int a)
> # 	{
> # 		return a;
> # 	}
> #
> # 	int* foo(int* a)
> # 	{
> # 		return a;
> # 	}
> # }
> #
> # void main()
> # {
> # 	Foo f = new Foo;
> # 	f.foo(2);
> # }
> 
> 
> Am I missing/mixing something about mixins ? I'd really like the mixin code to work... right now I have to make huge cut'n'pasting in my project :(

If one reads the mixin documents, one gets the impression that it is a method of inserting code _as if it had been coded in_. However, mixins are not exactly boilerplate code snippets. Which is a crying shame, if you ask me.

Using your example, one could have thought that it was as if you had coded ...

# class Foo
# {
#    int foo(int a)
#    {
#        return a;
#    }
#    int* foo(int* a)
#    {
#        return a;
#    }
#}
#void main()
#{
#    Foo f = new Foo;
#    f.foo(2);
#}

which compiles just fine. But using mixins you have to go over some stupid looking hurdles.

#template MFoo(T)
#{
#    T foo(T a)
#    {
#        return a;
#    }
#}
#class Foo
#{
#  mixin  MFoo!(int)  mint; alias mint.foo foo;
#  mixin  MFoo!(int*) mintp; alias mintp.foo foo;
#}
#void main()
#{
#    Foo f = new Foo;
#    f.foo(2);
#}

So, to repeat myself, mixins are not macros.

  mixin MFoo!(int)

does not exactly generate ...

  int foo(int a)
  {
    return a;
  }

as you would naturally expect. Its more like creating a variable declaration, and having two variables with the same name in the same scope is a conflict.

I think it is a mistake that one day Walter will see fit to correct.

-- 
Derek Parnell
Melbourne, Australia
http://www.dsource.org/projects/build v2.06 is now available. 04/May/2005
7/05/2005 4:25:35 AM

Derek Parnell wrote:
> So, to repeat myself, mixins are not macros. 
> 
>   mixin MFoo!(int)
> 
> does not exactly generate ...
> 
>   int foo(int a)
>   {
>     return a;
>   }
> 
> as you would naturally expect. Its more like creating a variable
> declaration, and having two variables with the same name in the same scope
> is a conflict.
> 
> I think it is a mistake that one day Walter will see fit to correct.


Sorry I haven't replied earlier, but only now I could get back to my comp for a longer while.
Thank you (and Sean) for helping me out with this issue, but I don't quite like the solution... I hope this problem will be fixed / resolved in future (or rather: Walter resolves it)
I've gone with another solution, which at least looks better in the implementation /* I'd have to define many of these mixin FooMixin1 .. FooMixinN as I'm using it for custom classes rather than for int and int* ... */ I'm just mixing in a single template which has the desired code generated by a python script (like a marco -> shame), lies in a separate file/module and at least works exactly as I want it to...


-- 
Tomasz Stachowiak  /+ a.k.a. h3r3tic +/