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			148 lines
		
	
	
	
		
			3.8 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			148 lines
		
	
	
	
		
			3.8 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| doctests = """
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| ########### Tests borrowed from or inspired by test_genexps.py ############
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| 
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| Test simple loop with conditional
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| 
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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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| 
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| Test simple nesting
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| 
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|     >>> [(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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| 
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| Test nesting with the inner expression dependent on the outer
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| 
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|     >>> [(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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| 
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| Make sure the induction variable is not exposed
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| 
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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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| 
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|     >>> i
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|     20
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| 
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| Verify that syntax error's are raised for listcomps used as lvalues
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| 
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|     >>> [y for y in (1,2)] = 10          # doctest: +IGNORE_EXCEPTION_DETAIL
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|     Traceback (most recent call last):
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|        ...
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|     SyntaxError: ...
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| 
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|     >>> [y for y in (1,2)] += 10         # doctest: +IGNORE_EXCEPTION_DETAIL
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|     Traceback (most recent call last):
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|        ...
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|     SyntaxError: ...
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| 
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| 
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| ########### Tests borrowed from or inspired by test_generators.py ############
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| 
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| Make a nested list comprehension that acts like range()
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| 
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|     >>> def frange(n):
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|     ...     return [i for i in range(n)]
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|     >>> frange(10)
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|     [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
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| 
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| Same again, only as a lambda expression instead of a function definition
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| 
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|     >>> lrange = lambda n:  [i for i in range(n)]
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|     >>> lrange(10)
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|     [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
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| 
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| Generators can call other generators:
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| 
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|     >>> def grange(n):
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|     ...     for x in [i for i in range(n)]:
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|     ...         yield x
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|     >>> list(grange(5))
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|     [0, 1, 2, 3, 4]
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| 
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| 
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| Make sure that None is a valid return value
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| 
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|     >>> [None for i in range(10)]
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|     [None, None, None, None, None, None, None, None, None, None]
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| 
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| ########### Tests for various scoping corner cases ############
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| 
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| Return lambdas that use the iteration variable as a default argument
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| 
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|     >>> items = [(lambda i=i: i) for i in range(5)]
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|     >>> [x() for x in items]
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|     [0, 1, 2, 3, 4]
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| 
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| Same again, only this time as a closure variable
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| 
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|     >>> items = [(lambda: i) for i in range(5)]
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|     >>> [x() for x in items]
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|     [4, 4, 4, 4, 4]
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| 
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| Another way to test that the iteration variable is local to the list comp
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| 
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|     >>> items = [(lambda: i) for i in range(5)]
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|     >>> i = 20
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|     >>> [x() for x in items]
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|     [4, 4, 4, 4, 4]
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| 
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| And confirm that a closure can jump over the list comp scope
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| 
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|     >>> items = [(lambda: y) for i in range(5)]
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|     >>> y = 2
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|     >>> [x() for x in items]
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|     [2, 2, 2, 2, 2]
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| 
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| We also repeat each of the above scoping tests inside a function
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| 
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|     >>> def test_func():
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|     ...     items = [(lambda i=i: i) for i in range(5)]
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|     ...     return [x() for x in items]
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|     >>> test_func()
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|     [0, 1, 2, 3, 4]
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| 
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|     >>> def test_func():
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|     ...     items = [(lambda: i) for i in range(5)]
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|     ...     return [x() for x in items]
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|     >>> test_func()
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|     [4, 4, 4, 4, 4]
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| 
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|     >>> def test_func():
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|     ...     items = [(lambda: i) for i in range(5)]
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|     ...     i = 20
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|     ...     return [x() for x in items]
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|     >>> test_func()
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|     [4, 4, 4, 4, 4]
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| 
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|     >>> def test_func():
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|     ...     items = [(lambda: y) for i in range(5)]
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|     ...     y = 2
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|     ...     return [x() for x in items]
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|     >>> test_func()
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|     [2, 2, 2, 2, 2]
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| 
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| """
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| 
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| 
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| __test__ = {'doctests' : doctests}
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| 
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| def test_main(verbose=None):
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|     import sys
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|     from test import support
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|     from test import test_listcomps
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|     support.run_doctest(test_listcomps, verbose)
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| 
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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 range(len(counts)):
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|             support.run_doctest(test_listcomps, 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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| 
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| if __name__ == "__main__":
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|     test_main(verbose=True)
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