[Python-Dev] accumulator display syntax

Guido van Rossum guido at python.org
Tue Oct 21 16:50:16 EDT 2003

>     Guido> I expect that most iterator comprehensions (we need a better
>     Guido> term!)
> You didn't like "lazy list comprehensions"?

No, because list comprehensions are no longer the fundamental building
blocks.  Generator expression sounds good to me now.

>     Guido> We can quibble about whether double parentheses are needed, ...
> You haven't convinced me that you're not going to want to toss out
> one of the two comprehension syntaxes and only retain the lazy
> semantics in Py3k.

Too many double negatives. :-)

Right now I feel like keeping both syntaxes, but declaring list
comprehensions syntactic sugar for list(generator expression).

> If that's the case and the current list comprehension syntax is
> better than the current crop of proposals, why even add (lazy
> list|iterator) comprehensions now?  Just make do without them until
> Py3k and make all list comprehensions lazy at that point.  There
> will be enough other bullets to bite that this shouldn't be a big
> deal (many programs will probably require significant rewriting
> anyway).

It's likely that generator experssions won't make it into Python 2.x
for any x, just because of the effort to get the community to accept
new syntax in general.

--Guido van Rossum (home page: http://www.python.org/~guido/)

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