If we're really looking for a builtin, wouldn't it be better to go the route of getattr/setattr and have something like getslice that could operate on both lists and iterators?
Such a builtin should probably be getitem() rather than getslice() (since getitem(iterable, slice(start, stop, step)) covers the getslice() case). However, I don't really see the point of this, since "from itertools import islice" is nearly as good as such a builtin.
More importantly, I don't see how this alters Guido's basic criticism that slicing a list and slicing an iterator represent fundamentally different concepts. (ie. if "itr[x]" is unacceptable, I don't see how changing the spelling to "getitem(itr, x)" could make it any more acceptable).
If slicing is taken as representing random access to a data structure (which seems to be Guido's view), then using it to represent sequential access to an item in or region of an iterator is not appropriate.
I'm not sure how compatible that viewpoint is with wanting Python 3k to be as heavily iterator based as 2.x is list based, but that's an issue for the future.
For myself, I don't attach such specific semantics to slicing (I see it as highly dependent on the type of object being sliced), and consider it obvious syntactic sugar for the itertools islice operation. As mentioned in my previous message, I also think the iterator/iterable distinction should be able to be ignored as much as possible, and the lack of syntactic support for working with iterators is the major factor that throws the distinction into a programmer's face. It currently makes the fact that some builtins return lists and others iterators somewhat inconvenient.
Those arguments have already failed to persuade Guido though, so I guess the idea is dead for the moment (unless/until someone comes up with a convincing argument that I haven't thought of).
Given Guido's lack of enthusiasm for *this* idea though, I'm not even going to venture into the realms of "+" on iterators defaulting to itertools.chain or "*" to itertools.repeat.
Cheers, Nick.
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Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
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http://boredomandlaziness.skystorm.net
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