[boost] Re: Deadline for the Standard Library TechnicalReport

From: Jason House (jhouse_at_[hidden])
Date: 2003-01-30 15:12:48

I'm sorry if I repeat some past discussion, I have not followed this
discussion thread from the beginning.  (I read the past several posts to
make sure I didn't write anything too stupid) 

I read http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2002/n1406.pdf
that genny referred to.

I have two comments about the proposal.

1. there is no mention of default parameters in the templated type. 
While I don't know how that would affect implementation details, it
seems like such a feature should be included.

example (of something that should be legal):
template <A,B=X,C=Y> class D;
template <A,B=Z> typedef E D<A,B,Y>;

2.  Section 2.5 (Different Declarations) rubs me the wrong way.  Thr
proposal does say that some people dislike this, and I guess I'm one of
them.

If 
template <A,B> class X;
template <A> typedef foo X<A,B>;
then I'm opposed to typeof(X<A,B>) != typeof(foo<A>)
After all
if
typedef bar int;
then typeof(bar) == typeof(int)  /* causes occasional dismay */

I'd like to see templates hold the same logical niche for both templated
and untemplated types.

It would be interesting to have a means of defining a new type via a
typedef-like declaration that did not share type equality, I just
wouldn't want it to be a normal looking typedef statement.

maybe
template <A,B> class X;
template <A> distincttypedef foo2 X<A,B>;
distincttypedef bar2 int;

Then typeof(foo2<A>) != typeof(X<A,B>)
and  typeof(bar2)    != typeof(int)
both seem natural to me... distincttypedef might not be the right future
syntax, but hopefully the idea is clear

Gennaro Prota wrote:
> 
> On Wed, 29 Jan 2003 12:43:49 -0600, "David B. Held"
> <dheld_at_[hidden]> wrote:
> 
> >Well, I thought Herb's proposal was more or less "definitive".  Is that
> >not what's likely to be presented to the committee?  If we got template
> >aliasing as you describe above, then Herb's proposal is just fine with
> >me.
> 
> But where is the true proposal? I just know this:
> 
> http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2002/n1406.pdf
> 
> which seems rather a magazine article to me.
> 
> Genny.
> 
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