Wishlist: iteration len()-type operator

[GoogleCodeExporter]

Rather than have an application provide an iterable list of objects (like,
say, 'changes') *and* a value like 'num_changes', it'd be right handy if
the template could simply ask for the length of the list in some way.

Original issue reported on code.google.com by cmpilato on 19 Dec 2008 at 6:57

[GoogleCodeExporter]

Actually, right now, we don't allow an iterable -- just sequences. There was a 
patch
a while back (gotta dig out from my mailbox) to allow for iterables. If that 
happens,
then you would not necessarily be able to do a len() call (sequences have 
length;
iterables do not).

That said, there will need to be an error if you attempt to take the length of a
scalar, and that same error could be used for iterables.

Did you have an idea for the syntax?

Original comment by gstein on 19 Dec 2008 at 7:18

[GoogleCodeExporter]

Oh. Idea for syntax. We had discussed .list-index at one point, noting that 
names
with a dash (not an underscore) would be reserved to ezt. Maybe the syntax 
could be:

  [foo.bar.list-len]

Other ideas?

Original comment by gstein on 19 Dec 2008 at 7:20

[GoogleCodeExporter]

I'm glad you remembered our conversation about syntax, because I didn't. :-) 
"list-len" seems fine.

Original comment by cmpilato on 19 Dec 2008 at 7:54

[gstein]

CC: @cmpilato