[Nathaniel Smith at numpy-discussion]Guido just formally acceptedPEP 465:https://mail.python.org/pipermail/python-dev/2014-April/133819.htmlhttp://legacy.python.org/dev/peps/pep-0465/#implementation-detailsYay.The next step is to implement it, in CPython and in numpy. I have timeto advise on this, but not to do it myself, so, any volunteers? Everwanted to hack on the interpreter itself, with BDFL guarantee yourpatch will be accepted (if correct)?The todo list for CPython is here:http://legacy.python.org/dev/peps/pep-0465/#implementation-detailsThere's one open question which is where the type slots should beadded. I'd just add them to PyNumberMethods and then if someoneobjects during patch review it can be changed.

Here's a first patch. It works, but needs more tests (associativity, precedence, __rmatmul__, etc...) and also docs. I can work on that tomorrow.

Here are changes to the operator module...

I've got to the point where I can do>>> import ast>>> ast.dump(ast.parse('a @ b'))"Module(body=[Expr(value=BinOp(left=Name(id='a', ctx=Load()), op=MatMult(), right=Name(id='b', ctx=Load())))])"I'll post a link to my bitbucket clone shortly.

Here is a nearly complete patch...

Wow! That was quick. And I am still fighting with bitbucket.  Maybe I should stop duplicating the effort at this point.

On Mon, Apr 7, 2014, at 22:09, Alexander Belopolsky wrote:> > Alexander Belopolsky added the comment:> > Wow! That was quick. And I am still fighting with bitbucket.  Maybe I> should stop duplicating the effort at this point.Sorry about that. I only saw the first message, where Nathaniel invitesan implementation. I didn't realize that was a direct quote from themailing list (not by you) and didn't notice you also assigned it toyourself.

Thanks for stepping in.  From a quick look at your patch I don't see anything that I would do much differently.I noticed some whitespace issues inInclude/token.h:-#define AT              49-#define RARROW          50-#define ELLIPSIS        51+#define AT              49+#define ATEQUAL50+#define RARROW          51+#define ELLIPSIS        52(Are you sure you want to re-enumerate RARROW and ELLIPSIS? Why not just give ATEQUAL the value of 52?)

+   .. versionadded:: 3.4Are you planning to use the time machine? :-)

On Mon, Apr 7, 2014, at 22:23, Alexander Belopolsky wrote:> > Alexander Belopolsky added the comment:> > Thanks for stepping in.  From a quick look at your patch I don't see> anything that I would do much differently.> > I noticed some whitespace issues inInclude/token.h:> > -#define AT              49     > -#define RARROW          50> -#define ELLIPSIS        51> +#define AT              49> +#define ATEQUAL                50> +#define RARROW          51> +#define ELLIPSIS        52> > (Are you sure you want to re-enumerate RARROW and ELLIPSIS? Why not just> give ATEQUAL the value of 52?)I thought it would be nicer if ATEQUAL was right after AT.

On Mon, Apr 7, 2014, at 22:25, Alexander Belopolsky wrote:> > Alexander Belopolsky added the comment:> > +   .. versionadded:: 3.4> > Are you planning to use the time machine? :-)Good catch. :)

Here's my latest and greatest version. I'll finish up after some sleep.

Here's what I consider a complete patch.

I think this patch is fairly straightforward, and I don't want it to rot, so here we go...

New changesetc553d8f72d65 by Benjamin Peterson in branch 'default':PEP 465: a dedicated infix operator for matrix multiplication (closes#21176)http://hg.python.org/cpython/rev/c553d8f72d65