Op 2005-12-10, Brian Beck schreef <[EMAIL PROTECTED]>:
> Antoon Pardon wrote:
>> Will it ever be possible to write things like:
>>
>> a = 4:9
>
> I made a silly recipe to do something like this a while ago, not that
> I'd recommend using it. But I also think it wouldn't be too far-fetched
> to allow slice creation using a syntax like the above...
The point is that the syntax "4:9" is already used for slice creation.
The python grammer is essentally saying that something like 4:9 is a
literal, just like strings and numbers, but that this specific literal
can only be used in a subscription.
Look at the following:
>>> import dis
>>> def foo():
... lst[[2,3,5]]
... lst[8:13:21]
...
>>> dis.dis(foo)
2 0 LOAD_GLOBAL 0 (lst)
3 LOAD_CONST 1 (2)
6 LOAD_CONST 2 (3)
9 LOAD_CONST 3 (5)
12 BUILD_LIST 3
15 BINARY_SUBSCR
16 POP_TOP
3 17 LOAD_GLOBAL 0 (lst)
20 LOAD_CONST 4 (8)
23 LOAD_CONST 5 (13)
26 LOAD_CONST 6 (21)
29 BUILD_SLICE 3
32 BINARY_SUBSCR
33 POP_TOP
34 LOAD_CONST 0 (None)
37 RETURN_VALUE
So you see that the slice is treated in an similar way
as the list. There is no reason why this shouldn't work
in case we want a slice in an assignment or a function
call.
--
Antoon Pardon
--
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