c++0x concepts in gcc call

c++0x concepts in gcc call

[Benjamin Kosnik]

Hello all!

Jason Merrill, Doug Gregor, and I invite all interested GCC hackers to
discuss implementation of the compiler and library parts of the
C++0x concepts proposals. This is to be a brainstorming session, where
we discuss the best way to complete the work, what can be taken from
existing branches, and how to smoothly transition between a
concept-enabled standard library and the current libstdc++. 

This will take place:

Thursday, January 24, 2008
10:00 am EST / 15:00 UTC

In order to secure enough lines for the teleconference, I'm asking
interested participants to RSVP to me privately. I will send out
call-in details 24hrs in advance, so please respond by then.

I plan to write up the minutes of this discussion and post them on the
gcc list for archiving and post-call discussion. 

best,
benjamin

Re: c++0x concepts in gcc call

[NightStrike]

On 1/21/08, Benjamin Kosnik <bkoz@redhat.com> wrote:
>
> Hello all!
>
> Jason Merrill, Doug Gregor, and I invite all interested GCC hackers to
> discuss implementation of the compiler and library parts of the
> C++0x concepts proposals. This is to be a brainstorming session, where
> we discuss the best way to complete the work, what can be taken from
> existing branches, and how to smoothly transition between a
> concept-enabled standard library and the current libstdc++.
>
> This will take place:
>
> Thursday, January 24, 2008
> 10:00 am EST / 15:00 UTC
>
> In order to secure enough lines for the teleconference, I'm asking
> interested participants to RSVP to me privately. I will send out
> call-in details 24hrs in advance, so please respond by then.
>
> I plan to write up the minutes of this discussion and post them on the
> gcc list for archiving and post-call discussion.

Will you allow people to call in as an observer, and not a participater?

Re: c++0x concepts in gcc call

[Benjamin Kosnik]

> Will you allow people to call in as an observer, and not a
> participater?

Yes, as long as we have enough lines for full participants.

Please note that I'll summarize this call in email afterward, so that
mechanism will also be available to lurkers.

-benjamin

Re: c++0x concepts in gcc call

[David Fang]

>> Will you allow people to call in as an observer, and not a
>> participater?

You beat me to the post!  I'm primarily interested in listening in, or 
reading a transcript at the very least.

> Yes, as long as we have enough lines for full participants.
>
> Please note that I'll summarize this call in email afterward, so that
> mechanism will also be available to lurkers.

Is there a chance of any sort of streaming audio broadcast instead of 
having to dial in?

Fang

David Fang
Computer Systems Laboratory
Electrical & Computer Engineering
Cornell University
http://www.csl.cornell.edu/~fang/
 	-- (2400 baud? Netscape 3.0?? lynx??? No problem!)

Re: c++0x concepts in gcc call

[Benjamin Kosnik]

> Is there a chance of any sort of streaming audio broadcast instead of 
> having to dial in?

Not for this call, sorry. 

-benjamin

Re: c++0x concepts in gcc call

[Doug Gregor]

On Jan 21, 2008 8:08 PM, Benjamin Kosnik <bkoz@redhat.com> wrote:
> Jason Merrill, Doug Gregor, and I invite all interested GCC hackers to
> discuss implementation of the compiler and library parts of the
> C++0x concepts proposals. This is to be a brainstorming session, where
> we discuss the best way to complete the work, what can be taken from
> existing branches, and how to smoothly transition between a
> concept-enabled standard library and the current libstdc++.

Some notes from the discussion in this call:

Organization:
 - We'll start a fresh branch in the FSF repository dedicated to concepts
   (it's branches/cxx0x-concepts-branch). Initially, Doug and Jason
   will be maintainers of this branch
 - We want to minimize the distance between this branch and mainline:
   * All non-concepts C++0x features will still go into mainline
   (unless they depend on concepts)
   * Type-checking of constrained templates depends on improved
   type-checking of C++98 templates (particularly, checking of
   non-dependent expressions), so we'll try to do all of this work in
   mainline
   * Doug will merge from mainline to branch regularly
 - Will salvage what we can from ConceptGCC: concept-checking,
   archetype generation, and parsing bits will be useful; type-checking
   of constrained templates needs to be reworked significantly.
 - We're not going to commit to any schedule, but it'll be a multi-year effort
 - We're going to delay any decisions about library issues for
   now. They won't matter until the front end supports enough of concepts
   to permit their use in the library

C++ front end:
 - Concepts representation:
    * Concepts, concept maps will be RECORD_TYPEs to reuse as much of
      that logic as is possible
    * Archetypes will probably need their own, new tree nodes
 - Same-type constraints and mapping to archetypes caused a lot of
   trouble in ConceptGCC: canonical types could simplify this
 - Constrained templates will create many new nodes in the internal
   representation that don't need to be around after a constrained
   template is type-checked; we might need to consider a stricter memory
   management scheme
 - Performance of the generated code was a problem with ConceptGCC,
   which Doug blames on the inliner. We should consider a limited form of
   inlining in the instantiation of constrained templates to avoid
   swamping the inliner with the forwarding functions in constrained
   templates.

For more information about the concepts branch, see
http://gcc.gnu.org/projects/cxx0x.html#concepts

For more information about ConceptGCC, see
http://www.generic-programming.org/software/ConceptGCC/

  - Doug

Re: c++0x concepts in gcc call

[Gerald Pfeifer]

On Fri, 25 Jan 2008, Doug Gregor wrote:
> Organization:
>  - We'll start a fresh branch in the FSF repository dedicated to concepts
>    (it's branches/cxx0x-concepts-branch). Initially, Doug and Jason
>    will be maintainers of this branch

Thanks for documenting this in svn.html!  Just one quip: in the patch
you documented this new branch but removed the reference to the old 
cxx0x-branch.

Shouldn't that be moved to the "Inactive Development Branches" instead?

Gerald

PS: Thinks for the excellent summary!

Re: c++0x concepts in gcc call

[Doug Gregor]

On Jan 27, 2008 8:23 PM, Gerald Pfeifer <gerald@pfeifer.com> wrote:
> On Fri, 25 Jan 2008, Doug Gregor wrote:
> > Organization:
> >  - We'll start a fresh branch in the FSF repository dedicated to concepts
> >    (it's branches/cxx0x-concepts-branch). Initially, Doug and Jason
> >    will be maintainers of this branch
>
> Thanks for documenting this in svn.html!  Just one quip: in the patch
> you documented this new branch but removed the reference to the old
> cxx0x-branch.
>
> Shouldn't that be moved to the "Inactive Development Branches" instead?

I was planning to kill the cxx0x-branch outright, because it has
nothing that isn't available on mainline (except a not-nearly-complete
delegating constructors implementation), and will not be used. If this
would be better handled by moving the entry to "Inactive Development
Branches", I'll certainly do that. But there isn't really anything of
value in the cxx0x-branch to keep around.

  - Doug

Re: c++0x concepts in gcc call

[Gerald Pfeifer]

On Sun, 27 Jan 2008, Doug Gregor wrote:
> I was planning to kill the cxx0x-branch outright, because it has
> nothing that isn't available on mainline (except a not-nearly-complete
> delegating constructors implementation), and will not be used. If this
> would be better handled by moving the entry to "Inactive Development
> Branches", I'll certainly do that.

Yes, for historical reasons it would be nice to have that branch 
documented there, with a note that/when it was merged into mainline
as for some of the other examples there.

Gerald

PS: Nice patch of yours that fixes seven PRs at once. :-)

Re: c++0x concepts in gcc call

[Doug Gregor]

On Mon, Jan 28, 2008 at 5:38 PM, Gerald Pfeifer <gerald@pfeifer.com> wrote:
> On Sun, 27 Jan 2008, Doug Gregor wrote:
>  > I was planning to kill the cxx0x-branch outright, because it has
>  > nothing that isn't available on mainline (except a not-nearly-complete
>  > delegating constructors implementation), and will not be used. If this
>  > would be better handled by moving the entry to "Inactive Development
>  > Branches", I'll certainly do that.
>
>  Yes, for historical reasons it would be nice to have that branch
>  documented there, with a note that/when it was merged into mainline
>  as for some of the other examples there.

Okay, done.

>  Gerald
>
>  PS: Nice patch of yours that fixes seven PRs at once. :-)

Now it's nine PRs :)

  - Doug

Index: svn.html
N===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/svn.html,v
retrieving revision 1.73
diff -u -r1.73 svn.html
--- svn.html    28 Jan 2008 15:19:04 -0000      1.73
+++ svn.html    29 Jan 2008 17:37:47 -0000
@@ -779,7 +779,12 @@
     zadeck@naturalbridge.com</a>&gt;
   </dd>

-
+  <dt>cxx0x-branch</dt>
+  <dd>This branch was for developed of C++0x features, and all
+  features developed on this branch have been merged to
+  mainline. Future C++0x features will be developed against mainline
+  or, in the case of concepts, on
+  the <a href="projects/cxx0x.html#concepts">cxx0x-concepts-branch</a>.</dd>
 </dl>

 </body>

Re: c++0x concepts in gcc call

[Gerald Pfeifer]

On Tue, 29 Jan 2008, Doug Gregor wrote:
> Okay, done.

Thanks!  I added the minor patch below on top.

Gerald

Index: svn.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/svn.html,v
retrieving revision 1.75
diff -u -3 -p -r1.75 svn.html
--- svn.html	3 Feb 2008 20:40:27 -0000	1.75
+++ svn.html	3 Feb 2008 21:58:16 -0000
@@ -778,7 +778,7 @@ be prefixed with the initials of the dis
   </dd>
 
   <dt>cxx0x-branch</dt>
-  <dd>This branch was for developed of C++0x features, and all
+  <dd>This branch was for the development of C++0x features, and all
   features developed on this branch have been merged to
   mainline. Future C++0x features will be developed against mainline
   or, in the case of concepts, on