1# mode: run
2# tag: generators, lambda
3
4def genexpr():
5    """
6    >>> genexpr()
7    [0, 2, 4, 6, 8]
8    """
9    x = 'abc'
10    result = list( x*2 for x in range(5) )
11    assert x == 'abc' # don't leak
12    return result
13
14def genexpr_if():
15    """
16    >>> genexpr_if()
17    [0, 4, 8]
18    """
19    x = 'abc'
20    result = list( x*2 for x in range(5) if x % 2 == 0 )
21    assert x == 'abc' # don't leak
22    return result
23
24def genexpr_if_false():
25    """
26    >>> genexpr_if_false()
27    []
28    """
29    x = 'abc'
30    result = list( x*2 for x in range(5) if False )
31    assert x == 'abc' # don't leak
32    return result
33
34def genexpr_with_lambda():
35    """
36    >>> genexpr_with_lambda()
37    [0, 4, 8]
38    """
39    x = 'abc'
40    result = list( x*2 for x in range(5) if (lambda x:x % 2)(x) == 0 )
41    assert x == 'abc' # don't leak
42    return result
43
44def genexpr_of_lambdas(int N):
45    """
46    >>> [ (f(), g()) for f,g in genexpr_of_lambdas(5) ]
47    [(0, 0), (1, 2), (2, 4), (3, 6), (4, 8)]
48    """
49    return ( ((lambda : x), (lambda : x*2)) for x in range(N) )
50
51
52def genexpr_with_bool_binop(values):
53    """
54    >>> values = [(1, 2, 3), (None, 4, None), (5, None, 6)]
55    >>> genexpr_with_bool_binop(values)
56    [(1, 2, 3), ('X', 4, 'X'), (5, 'X', 6)]
57    """
58    # copied from CPython's test_itertools.py
59    return [tuple((e is None and 'X' or e) for e in t) for t in values]
60