First I can tell you I suck at explaining. Anyway, here goes:

Imagine; you're writing a memory modelling class as a base class for other classes, this class is put in a template, but has it's own public interface per template instance since it's return types for functions are different per template. So you start with:

#template Memory(T) {
# class Memory {
#  T[] data;
#  int size() { ... }
#  T[] getData() { return data; }
# }
#}

Then, it's clear you would like to make an interface for it, so that later you may write different types of memory classes:

#template Memory(T) {
# interface Interface {
#  int size();
#  T[] getData();
# }
# class Memory : Interface {
#  T[] data;
#  int size() { ... }
#  T[] getData() { return data; }
# }
#}

That is a no go for the compiler if you're using the automatic associating
thingy (template NAME(T) class FOO { T ... }). So, what do you do? You name it
differently:

#template Memory(T) {
# interface Interface {
#  int size();
#  T[] getData();
# }
# class Basic : Interface {
#  T[] data;
#  int size() { ... }
#  T[] getData() { return data; }
# }
#}

Imagine you'd now want to use this model on a new type, a stack type (lot's of imagination here, heh, just trying to make absolute use of interfaces, since that would be interesting!). But, because this is a stack type, and you want it to be a container, you want it to be a template too. Besides that, you also want to be able to write different types of stacks, so you use interfaces so it won't break compatability with classes that will inherit either one of them stack types (which then have the interface). So, then, same small problem:

#template Stack(T) {
# class Stack : Memory!(T).Basic { ... }

that is a no go, you'd have to make it Basic again once you want to put in an interface. How many people are willing to use a STL that would require them to type this out loud:

Stack!(int).Basic

And no, you cannot make an alias (maybe you can prove me wrong but I've been using those for a while), it's a template, and you cannot magically make it return a type. You 'seem to be able' though, but it seems it doesn't work when you put interfaces or other things in them. What I want is that

Stack!(int) would be the same as Stack!(int).Basic

I think it's supposed to work. I thought about all kinds of possible ways to fix this but nothing comes up. It would be so cool if it worked, you could make uber templates, where you can make everything work to your abidding, make debugger versions where it keeps track of every operation, etc etc. Though that's more naziland... Oh right, uber-templates. ;)

Complete examples:

// a memory model
http://svn.dsource.org/svn/projects/dragon-stl/trunk/0.01_0101/memory.d
// the stack model that usees the memory model, yet without interfaces, and
shows lengthy use of template (though it would be less of a problem if it only
happened here)
http://svn.dsource.org/svn/projects/dragon-stl/trunk/0.01_0101/stack.d

I hope someone can prove me wrong.

"Joey Peters" <Joey_member@pathlink.com> wrote in message news:ci18np$2se3$1@digitaldaemon.com...
> First I can tell you I suck at explaining. Anyway, here goes:
>
> Imagine; you're writing a memory modelling class as a base class for other classes, this class is put in a template, but has it's own public
interface per
> template instance since it's return types for functions are different per template. So you start with:
>
> #template Memory(T) {
> # class Memory {
> #  T[] data;
> #  int size() { ... }
> #  T[] getData() { return data; }
> # }
> #}
>
> Then, it's clear you would like to make an interface for it, so that later
you
> may write different types of memory classes:
>
> #template Memory(T) {
> # interface Interface {
> #  int size();
> #  T[] getData();
> # }
> # class Memory : Interface {
> #  T[] data;
> #  int size() { ... }
> #  T[] getData() { return data; }
> # }
> #}
>
> That is a no go for the compiler if you're using the automatic associating
> thingy (template NAME(T) class FOO { T ... }). So, what do you do? You
name it
> differently:
>
> #template Memory(T) {
> # interface Interface {
> #  int size();
> #  T[] getData();
> # }
> # class Basic : Interface {
> #  T[] data;
> #  int size() { ... }
> #  T[] getData() { return data; }
> # }
> #}
>
> Imagine you'd now want to use this model on a new type, a stack type
(lot's of
> imagination here, heh, just trying to make absolute use of interfaces,
since
> that would be interesting!). But, because this is a stack type, and you
want it
> to be a container, you want it to be a template too. Besides that, you
also want
> to be able to write different types of stacks, so you use interfaces so it
won't
> break compatability with classes that will inherit either one of them
stack
> types (which then have the interface). So, then, same small problem:
>
> #template Stack(T) {
> # class Stack : Memory!(T).Basic { ... }
>
> that is a no go, you'd have to make it Basic again once you want to put in
an
> interface. How many people are willing to use a STL that would require
them to
> type this out loud:
>
> Stack!(int).Basic

How about splitting the template into two templates MemoryInterface and MemoryBasic, wouldn't that solve a problem. (although i don't see it as a problem) ;)

> And no, you cannot make an alias (maybe you can prove me wrong but I've
been
> using those for a while), it's a template, and you cannot magically make
it
> return a type. You 'seem to be able' though, but it seems it doesn't work
when
> you put interfaces or other things in them. What I want is that
>
> Stack!(int) would be the same as Stack!(int).Basic
>
> I think it's supposed to work. I thought about all kinds of possible ways
to fix
> this but nothing comes up. It would be so cool if it worked, you could
make uber
> templates, where you can make everything work to your abidding, make
debugger
> versions where it keeps track of every operation, etc etc. Though that's
more
> naziland... Oh right, uber-templates. ;)
>
> Complete examples:
>
> // a memory model http://svn.dsource.org/svn/projects/dragon-stl/trunk/0.01_0101/memory.d // the stack model that usees the memory model, yet without interfaces,
and
> shows lengthy use of template (though it would be less of a problem if it
only
> happened here) http://svn.dsource.org/svn/projects/dragon-stl/trunk/0.01_0101/stack.d
>
> I hope someone can prove me wrong.
>
>

Disambiguate types with names and declare one datatype per template

interface IMemory(T) ...
interface IStack(T) : IMemory!(T) ...
class Memory(T) : IMemory!(T) ...
class Stack(T) : IStack!(T), Memory!(T) ...

Is this sufficient to solve your problem?

In article <ci1g95$2vdt$1@digitaldaemon.com>, Bent Rasmussen says...
>
>Disambiguate types with names and declare one datatype per template
>
>interface IMemory(T) ...
>interface IStack(T) : IMemory!(T) ...
>class Memory(T) : IMemory!(T) ...
>class Stack(T) : IStack!(T), Memory!(T) ...
>
>Is this sufficient to solve your problem?
>
>

That would work, thanks.