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37c0844b35
Incorrect code was generated for: foo(a = i for i in range(10)) This should have generated a SyntaxError. Fix the Grammar so it raises a SyntaxError and test it. I'm uncertain whether this should be backported. It makes something that was Syntactically valid invalid. However, the code would either be completely broken or do the wrong thing.
281 lines
7.1 KiB
Python
281 lines
7.1 KiB
Python
doctests = """
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Test simple loop with conditional
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>>> sum(i*i for i in range(100) if i&1 == 1)
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166650
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Test simple nesting
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>>> list((i,j) for i in range(3) for j in range(4) )
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[(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
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Test nesting with the inner expression dependent on the outer
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>>> list((i,j) for i in range(4) for j in range(i) )
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[(1, 0), (2, 0), (2, 1), (3, 0), (3, 1), (3, 2)]
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Make sure the induction variable is not exposed
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>>> i = 20
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>>> sum(i*i for i in range(100))
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328350
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>>> i
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20
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Test first class
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>>> g = (i*i for i in range(4))
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>>> type(g)
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<type 'generator'>
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>>> list(g)
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[0, 1, 4, 9]
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Test direct calls to next()
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>>> g = (i*i for i in range(3))
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>>> g.next()
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0
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>>> g.next()
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1
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>>> g.next()
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4
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>>> g.next()
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Traceback (most recent call last):
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File "<pyshell#21>", line 1, in -toplevel-
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g.next()
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StopIteration
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Does it stay stopped?
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>>> g.next()
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Traceback (most recent call last):
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File "<pyshell#21>", line 1, in -toplevel-
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g.next()
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StopIteration
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>>> list(g)
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[]
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Test running gen when defining function is out of scope
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>>> def f(n):
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... return (i*i for i in xrange(n))
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>>> list(f(10))
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[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
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>>> def f(n):
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... return ((i,j) for i in xrange(3) for j in xrange(n))
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>>> list(f(4))
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[(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
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>>> def f(n):
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... return ((i,j) for i in xrange(3) for j in xrange(4) if j in xrange(n))
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>>> list(f(4))
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[(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
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>>> list(f(2))
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[(0, 0), (0, 1), (1, 0), (1, 1), (2, 0), (2, 1)]
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Verify that parenthesis are required in a statement
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>>> def f(n):
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... return i*i for i in xrange(n)
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Traceback (most recent call last):
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...
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SyntaxError: invalid syntax
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Verify that parenthesis are required when used as a keyword argument value
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>>> dict(a = i for i in xrange(10))
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Traceback (most recent call last):
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...
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SyntaxError: invalid syntax
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Verify that parenthesis are required when used as a keyword argument value
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>>> dict(a = (i for i in xrange(10))) #doctest: +ELLIPSIS
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{'a': <generator object at ...>}
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Verify early binding for the outermost for-expression
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>>> x=10
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>>> g = (i*i for i in range(x))
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>>> x = 5
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>>> list(g)
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[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
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Verify that the outermost for-expression makes an immediate check
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for iterability
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>>> (i for i in 6)
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Traceback (most recent call last):
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File "<pyshell#4>", line 1, in -toplevel-
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(i for i in 6)
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TypeError: iteration over non-sequence
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Verify late binding for the outermost if-expression
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>>> include = (2,4,6,8)
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>>> g = (i*i for i in range(10) if i in include)
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>>> include = (1,3,5,7,9)
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>>> list(g)
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[1, 9, 25, 49, 81]
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Verify late binding for the innermost for-expression
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>>> g = ((i,j) for i in range(3) for j in range(x))
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>>> x = 4
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>>> list(g)
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[(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
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Verify re-use of tuples (a side benefit of using genexps over listcomps)
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>>> tupleids = map(id, ((i,i) for i in xrange(10)))
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>>> max(tupleids) - min(tupleids)
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0
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Verify that syntax error's are raised for genexps used as lvalues
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>>> (y for y in (1,2)) = 10
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Traceback (most recent call last):
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...
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SyntaxError: assignment to generator expression not possible (<doctest test.test_genexps.__test__.doctests[40]>, line 1)
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>>> (y for y in (1,2)) += 10
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Traceback (most recent call last):
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...
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SyntaxError: augmented assignment to generator expression not possible (<doctest test.test_genexps.__test__.doctests[41]>, line 1)
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########### Tests borrowed from or inspired by test_generators.py ############
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Make a generator that acts like range()
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>>> yrange = lambda n: (i for i in xrange(n))
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>>> list(yrange(10))
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[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
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Generators always return to the most recent caller:
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>>> def creator():
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... r = yrange(5)
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... print "creator", r.next()
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... return r
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>>> def caller():
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... r = creator()
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... for i in r:
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... print "caller", i
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>>> caller()
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creator 0
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caller 1
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caller 2
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caller 3
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caller 4
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Generators can call other generators:
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>>> def zrange(n):
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... for i in yrange(n):
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... yield i
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>>> list(zrange(5))
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[0, 1, 2, 3, 4]
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Verify that a gen exp cannot be resumed while it is actively running:
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>>> g = (me.next() for i in xrange(10))
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>>> me = g
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>>> me.next()
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Traceback (most recent call last):
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File "<pyshell#30>", line 1, in -toplevel-
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me.next()
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File "<pyshell#28>", line 1, in <generator expression>
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g = (me.next() for i in xrange(10))
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ValueError: generator already executing
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Verify exception propagation
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>>> g = (10 // i for i in (5, 0, 2))
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>>> g.next()
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2
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>>> g.next()
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Traceback (most recent call last):
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File "<pyshell#37>", line 1, in -toplevel-
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g.next()
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File "<pyshell#35>", line 1, in <generator expression>
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g = (10 // i for i in (5, 0, 2))
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ZeroDivisionError: integer division or modulo by zero
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>>> g.next()
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Traceback (most recent call last):
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File "<pyshell#38>", line 1, in -toplevel-
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g.next()
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StopIteration
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Make sure that None is a valid return value
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>>> list(None for i in xrange(10))
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[None, None, None, None, None, None, None, None, None, None]
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Check that generator attributes are present
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>>> g = (i*i for i in range(3))
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>>> expected = set(['gi_frame', 'gi_running', 'next'])
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>>> set(attr for attr in dir(g) if not attr.startswith('__')) >= expected
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True
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>>> print g.next.__doc__
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x.next() -> the next value, or raise StopIteration
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>>> import types
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>>> isinstance(g, types.GeneratorType)
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True
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Check the __iter__ slot is defined to return self
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>>> iter(g) is g
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True
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Verify that the running flag is set properly
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>>> g = (me.gi_running for i in (0,1))
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>>> me = g
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>>> me.gi_running
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0
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>>> me.next()
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1
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>>> me.gi_running
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0
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Verify that genexps are weakly referencable
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>>> import weakref
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>>> g = (i*i for i in range(4))
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>>> wr = weakref.ref(g)
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>>> wr() is g
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True
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>>> p = weakref.proxy(g)
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>>> list(p)
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[0, 1, 4, 9]
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"""
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__test__ = {'doctests' : doctests}
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def test_main(verbose=None):
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import sys
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from test import test_support
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from test import test_genexps
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test_support.run_doctest(test_genexps, verbose)
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# verify reference counting
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if verbose and hasattr(sys, "gettotalrefcount"):
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import gc
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counts = [None] * 5
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for i in xrange(len(counts)):
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test_support.run_doctest(test_genexps, verbose)
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gc.collect()
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counts[i] = sys.gettotalrefcount()
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print counts
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if __name__ == "__main__":
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test_main(verbose=True)
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