Benjamin Peterson <[EMAIL PROTECTED]> added the comment:
This is because list comprehensions are implemented as functions in 3.0
so their scope is not leaked out to the rest of the function.
Here is the bytecode for 2.6:
>>> dis.dis(f)
2 0 BUILD_LIST 0
3 DUP_TOP
4 STORE_FAST 0 (_[1])
7 LOAD_CONST 5 ((1, 2, 3))
10 GET_ITER
>> 11 FOR_ITER 14 (to 28)
14 STORE_FAST 1 (x)
17 LOAD_FAST 0 (_[1])
20 LOAD_FAST 1 (x)
23 YIELD_VALUE
24 LIST_APPEND
25 JUMP_ABSOLUTE 11
>> 28 DELETE_FAST 0 (_[1])
31 STORE_FAST 1 (x)
3 34 LOAD_CONST 4 (5)
37 YIELD_VALUE
38 POP_TOP
4 39 LOAD_FAST 1 (x)
42 YIELD_VALUE
43 POP_TOP
44 LOAD_CONST 0 (None)
47 RETURN_VALUE
and here it is for 3.0:
>>> dis.dis(f)
2 0 LOAD_CONST 1 (<code object <listcomp> at
0x740770, file "<stdin>", line 2>)
3 MAKE_FUNCTION 0
6 LOAD_CONST 6 ((1, 2, 3))
9 GET_ITER
10 CALL_FUNCTION 1
13 STORE_FAST 0 (x)
3 16 LOAD_CONST 5 (5)
19 YIELD_VALUE
20 POP_TOP
4 21 LOAD_FAST 0 (x)
24 YIELD_VALUE
25 POP_TOP
26 LOAD_CONST 0 (None)
29 RETURN_VALUE
----------
nosy: +benjamin.peterson
type: -> behavior
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Python tracker <[EMAIL PROTECTED]>
<http://bugs.python.org/issue3267>
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