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SF bug #436207: "if 0: yield x" is ignored.
Not anymore <wink>. Pure hack. Doesn't fix any other "if 0:" glitches.
This commit is contained in:
Tim Peters
parent
3e7b1a04a0
commit
b6c3ceae79
@ -431,6 +431,9 @@ in increasing order, where i,j,k >= 0. Trickier than it may look at first!
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Try writing it without generators, and correctly, and without generating
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3 internal results for each result output.
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XXX Suspect there's memory leaks in this one; definitely in the next
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XXX version.
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>>> def times(n, g):
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... for i in g:
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... yield n * i
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@ -482,6 +485,8 @@ namespace renaming trick. The *pretty* part is that the times() and merge()
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functions can be reused as-is, because they only assume their stream
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arguments are iterable -- a LazyList is the same as a generator to times().
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XXX Massive memory leaks in this; see Python-Iterators.
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>>> class LazyList:
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... def __init__(self, g):
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... self.sofar = []
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@ -514,7 +519,8 @@ arguments are iterable -- a LazyList is the same as a generator to times().
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[400, 405, 432, 450, 480, 486, 500, 512, 540, 576, 600, 625, 640, 648, 675]
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"""
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# syntax_tests mostly provokes SyntaxErrors.
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# syntax_tests mostly provokes SyntaxErrors. Also fiddling with #if 0
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# hackery.
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syntax_tests = """
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@ -588,13 +594,128 @@ But this is fine:
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... return
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>>> list(f())
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[12, 666]
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>>> def f():
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... if 0:
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... yield 1
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>>> type(f())
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<type 'generator'>
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>>> def f():
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... if "":
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... yield None
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>>> type(f())
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<type 'generator'>
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>>> def f():
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... return
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... try:
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... if x==4:
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... pass
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... elif 0:
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... try:
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... 1/0
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... except SyntaxError:
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... pass
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... else:
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... if 0:
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... while 12:
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... x += 1
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... yield 2 # don't blink
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... f(a, b, c, d, e)
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... else:
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... pass
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... except:
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... x = 1
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... return
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>>> type(f())
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<type 'generator'>
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>>> def f():
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... if 0:
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... def g():
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... yield 1
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...
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>>> type(f())
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<type 'None'>
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>>> def f():
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... if 0:
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... class C:
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... def __init__(self):
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... yield 1
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... def f(self):
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... yield 2
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>>> type(f())
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<type 'None'>
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"""
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__test__ = {"tut": tutorial_tests,
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"pep": pep_tests,
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"email": email_tests,
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"fun": fun_tests,
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"syntax": syntax_tests}
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x_tests = """
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>>> def firstn(g, n):
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... return [g.next() for i in range(n)]
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>>> def times(n, g):
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... for i in g:
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... yield n * i
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>>> def merge(g, h):
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... ng = g.next()
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... nh = h.next()
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... while 1:
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... if ng < nh:
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... yield ng
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... ng = g.next()
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... elif ng > nh:
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... yield nh
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... nh = h.next()
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... else:
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... yield ng
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... ng = g.next()
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... nh = h.next()
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>>> class LazyList:
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... def __init__(self, g):
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... self.sofar = []
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... self.fetch = g.next
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...
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... def __getitem__(self, i):
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... sofar, fetch = self.sofar, self.fetch
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... while i >= len(sofar):
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... sofar.append(fetch())
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... return sofar[i]
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>>> def m235():
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... yield 1
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... # Gack: m235 below actually refers to a LazyList.
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... me_times2 = times(2, m235)
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... me_times3 = times(3, m235)
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... me_times5 = times(5, m235)
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... for i in merge(merge(me_times2,
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... me_times3),
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... me_times5):
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... yield i
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>>> m235 = LazyList(m235())
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>>> for i in range(5):
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... x = [m235[j] for j in range(15*i, 15*(i+1))]
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[1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24]
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[25, 27, 30, 32, 36, 40, 45, 48, 50, 54, 60, 64, 72, 75, 80]
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[81, 90, 96, 100, 108, 120, 125, 128, 135, 144, 150, 160, 162, 180, 192]
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[200, 216, 225, 240, 243, 250, 256, 270, 288, 300, 320, 324, 360, 375, 384]
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[400, 405, 432, 450, 480, 486, 500, 512, 540, 576, 600, 625, 640, 648, 675]
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"""
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__test__ = {"tut": tutorial_tests, # clean
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"pep": pep_tests, # clean
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"email": email_tests, # clean
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"fun": fun_tests, # leaks
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"syntax": syntax_tests # clean
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#"x": x_tests
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}
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# Magic test name that regrtest.py invokes *after* importing this module.
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# This worms around a bootstrap problem.
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@ -605,7 +726,7 @@ def test_main():
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if 0:
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# Temporary block to help track down leaks. So far, the blame
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# has fallen mostly on doctest.
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for i in range(1000):
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for i in range(5000):
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doctest.master = None
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doctest.testmod(test_generators)
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else:
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@ -4840,6 +4840,34 @@ symtable_add_def_o(struct symtable *st, PyObject *dict,
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#define symtable_add_use(ST, NAME) symtable_add_def((ST), (NAME), USE)
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/* Look for a yield stmt under n. Return 1 if found, else 0. */
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static int
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look_for_yield(node *n)
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{
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int i;
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for (i = 0; i < NCH(n); ++i) {
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node *kid = CHILD(n, i);
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switch (TYPE(kid)) {
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case classdef:
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case funcdef:
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/* Stuff in nested functions and classes can't make
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the parent a generator. */
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return 0;
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case yield_stmt:
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return 1;
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default:
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if (look_for_yield(kid))
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return 1;
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}
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}
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return 0;
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}
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static void
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symtable_node(struct symtable *st, node *n)
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{
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@ -4883,8 +4911,12 @@ symtable_node(struct symtable *st, node *n)
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}
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case if_stmt:
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for (i = 0; i + 3 < NCH(n); i += 4) {
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if (is_constant_false(NULL, (CHILD(n, i + 1))))
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if (is_constant_false(NULL, (CHILD(n, i + 1)))) {
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if (st->st_cur->ste_generator == 0)
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st->st_cur->ste_generator =
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look_for_yield(CHILD(n, i+3));
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continue;
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}
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symtable_node(st, CHILD(n, i + 1));
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symtable_node(st, CHILD(n, i + 3));
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}
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