Hide list comp variables and support set comprehensions

1 files changed, 444 insertions, 0 deletions

diff --git a/Lib/test/test_listcomps.py b/Lib/test/test_listcomps.py
new file mode 100644
index 0000000..bef4fff
--- /dev/null
+++ b/Lib/test/test_listcomps.py
@@ -0,0 +1,444 @@
+doctests = """
+########### Tests borrowed from or inspired by test_genexps.py ############
+
+Test simple loop with conditional
+
+    >>> sum([i*i for i in range(100) if i&1 == 1])
+    166650
+
+Test simple nesting
+
+    >>> [(i,j) for i in range(3) for j in range(4)]
+    [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
+
+Test nesting with the inner expression dependent on the outer
+
+    >>> [(i,j) for i in range(4) for j in range(i)]
+    [(1, 0), (2, 0), (2, 1), (3, 0), (3, 1), (3, 2)]
+
+Make sure the induction variable is not exposed
+
+    >>> i = 20
+    >>> sum([i*i for i in range(100)])
+    328350
+
+    >>> i
+    20
+
+Verify that syntax error's are raised for listcomps used as lvalues
+
+    >>> [y for y in (1,2)] = 10          # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+       ...
+    SyntaxError: ...
+
+    >>> [y for y in (1,2)] += 10         # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+       ...
+    SyntaxError: ...
+
+
+########### Tests borrowed from or inspired by test_generators.py ############
+
+Make a nested list comprehension that acts like range()
+
+    >>> def frange(n):
+    ...     return [i for i in xrange(n)]
+    >>> frange(10)
+    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+Same again, only as a lambda expression instead of a function definition
+
+    >>> lrange = lambda n:  [i for i in xrange(n)]
+    >>> lrange(10)
+    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+Generators can call other generators:
+
+    >>> def grange(n):
+    ...     for x in [i for i in xrange(n)]:
+    ...         yield x
+    >>> list(grange(5))
+    [0, 1, 2, 3, 4]
+
+
+Make sure that None is a valid return value
+
+    >>> [None for i in xrange(10)]
+    [None, None, None, None, None, None, None, None, None, None]
+
+########### Tests for various scoping corner cases ############
+
+Return lambdas that use the iteration variable as a default argument
+
+    >>> items = [(lambda i=i: i) for i in range(5)]
+    >>> [x() for x in items]
+    [0, 1, 2, 3, 4]
+
+Same again, only this time as a closure variable
+
+    >>> items = [(lambda: i) for i in range(5)]
+    >>> [x() for x in items]
+    [4, 4, 4, 4, 4]
+
+Another way to test that the iteration variable is local to the list comp
+
+    >>> items = [(lambda: i) for i in range(5)]
+    >>> i = 20
+    >>> [x() for x in items]
+    [4, 4, 4, 4, 4]
+
+And confirm that a closure can jump over the list comp scope
+
+    >>> items = [(lambda: y) for i in range(5)]
+    >>> y = 2
+    >>> [x() for x in items]
+    [2, 2, 2, 2, 2]
+
+We also repeat each of the above scoping tests inside a function
+
+    >>> def test_func():
+    ...     items = [(lambda i=i: i) for i in range(5)]
+    ...     return [x() for x in items]
+    >>> test_func()
+    [0, 1, 2, 3, 4]
+
+    >>> def test_func():
+    ...     items = [(lambda: i) for i in range(5)]
+    ...     return [x() for x in items]
+    >>> test_func()
+    [4, 4, 4, 4, 4]
+
+    >>> def test_func():
+    ...     items = [(lambda: i) for i in range(5)]
+    ...     i = 20
+    ...     return [x() for x in items]
+    >>> test_func()
+    [4, 4, 4, 4, 4]
+
+    >>> def test_func():
+    ...     items = [(lambda: y) for i in range(5)]
+    ...     y = 2
+    ...     return [x() for x in items]
+    >>> test_func()
+    [2, 2, 2, 2, 2]
+
+"""
+
+
+__test__ = {'doctests' : doctests}
+
+def test_main(verbose=None):
+    import sys
+    from test import test_support
+    from test import test_listcomps
+    test_support.run_doctest(test_listcomps, verbose)
+
+    # verify reference counting
+    if verbose and hasattr(sys, "gettotalrefcount"):
+        import gc
+        counts = [None] * 5
+        for i in xrange(len(counts)):
+            test_support.run_doctest(test_genexps, verbose)
+            gc.collect()
+            counts[i] = sys.gettotalrefcount()
+        print(counts)
+
+if __name__ == "__main__":
+    test_main(verbose=True)
+doctests = """
+########### Tests borrowed from or inspired by test_genexps.py ############
+
+Test simple loop with conditional
+
+    >>> sum([i*i for i in range(100) if i&1 == 1])
+    166650
+
+Test simple nesting
+
+    >>> [(i,j) for i in range(3) for j in range(4)]
+    [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
+
+Test nesting with the inner expression dependent on the outer
+
+    >>> [(i,j) for i in range(4) for j in range(i)]
+    [(1, 0), (2, 0), (2, 1), (3, 0), (3, 1), (3, 2)]
+
+Make sure the induction variable is not exposed
+
+    >>> i = 20
+    >>> sum([i*i for i in range(100)])
+    328350
+
+    >>> i
+    20
+
+Verify that syntax error's are raised for listcomps used as lvalues
+
+    >>> [y for y in (1,2)] = 10          # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+       ...
+    SyntaxError: ...
+
+    >>> [y for y in (1,2)] += 10         # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+       ...
+    SyntaxError: ...
+
+
+########### Tests borrowed from or inspired by test_generators.py ############
+
+Make a nested list comprehension that acts like range()
+
+    >>> def frange(n):
+    ...     return [i for i in xrange(n)]
+    >>> frange(10)
+    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+Same again, only as a lambda expression instead of a function definition
+
+    >>> lrange = lambda n:  [i for i in xrange(n)]
+    >>> lrange(10)
+    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+Generators can call other generators:
+
+    >>> def grange(n):
+    ...     for x in [i for i in xrange(n)]:
+    ...         yield x
+    >>> list(grange(5))
+    [0, 1, 2, 3, 4]
+
+
+Make sure that None is a valid return value
+
+    >>> [None for i in xrange(10)]
+    [None, None, None, None, None, None, None, None, None, None]
+
+########### Tests for various scoping corner cases ############
+
+Return lambdas that use the iteration variable as a default argument
+
+    >>> items = [(lambda i=i: i) for i in range(5)]
+    >>> [x() for x in items]
+    [0, 1, 2, 3, 4]
+
+Same again, only this time as a closure variable
+
+    >>> items = [(lambda: i) for i in range(5)]
+    >>> [x() for x in items]
+    [4, 4, 4, 4, 4]
+
+Another way to test that the iteration variable is local to the list comp
+
+    >>> items = [(lambda: i) for i in range(5)]
+    >>> i = 20
+    >>> [x() for x in items]
+    [4, 4, 4, 4, 4]
+
+And confirm that a closure can jump over the list comp scope
+
+    >>> items = [(lambda: y) for i in range(5)]
+    >>> y = 2
+    >>> [x() for x in items]
+    [2, 2, 2, 2, 2]
+
+We also repeat each of the above scoping tests inside a function
+
+    >>> def test_func():
+    ...     items = [(lambda i=i: i) for i in range(5)]
+    ...     return [x() for x in items]
+    >>> test_func()
+    [0, 1, 2, 3, 4]
+
+    >>> def test_func():
+    ...     items = [(lambda: i) for i in range(5)]
+    ...     return [x() for x in items]
+    >>> test_func()
+    [4, 4, 4, 4, 4]
+
+    >>> def test_func():
+    ...     items = [(lambda: i) for i in range(5)]
+    ...     i = 20
+    ...     return [x() for x in items]
+    >>> test_func()
+    [4, 4, 4, 4, 4]
+
+    >>> def test_func():
+    ...     items = [(lambda: y) for i in range(5)]
+    ...     y = 2
+    ...     return [x() for x in items]
+    >>> test_func()
+    [2, 2, 2, 2, 2]
+
+"""
+
+
+__test__ = {'doctests' : doctests}
+
+def test_main(verbose=None):
+    import sys
+    from test import test_support
+    from test import test_listcomps
+    test_support.run_doctest(test_listcomps, verbose)
+
+    # verify reference counting
+    if verbose and hasattr(sys, "gettotalrefcount"):
+        import gc
+        counts = [None] * 5
+        for i in xrange(len(counts)):
+            test_support.run_doctest(test_genexps, verbose)
+            gc.collect()
+            counts[i] = sys.gettotalrefcount()
+        print(counts)
+
+if __name__ == "__main__":
+    test_main(verbose=True)
+doctests = """
+########### Tests borrowed from or inspired by test_genexps.py ############
+
+Test simple loop with conditional
+
+    >>> sum([i*i for i in range(100) if i&1 == 1])
+    166650
+
+Test simple nesting
+
+    >>> [(i,j) for i in range(3) for j in range(4)]
+    [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
+
+Test nesting with the inner expression dependent on the outer
+
+    >>> [(i,j) for i in range(4) for j in range(i)]
+    [(1, 0), (2, 0), (2, 1), (3, 0), (3, 1), (3, 2)]
+
+Make sure the induction variable is not exposed
+
+    >>> i = 20
+    >>> sum([i*i for i in range(100)])
+    328350
+
+    >>> i
+    20
+
+Verify that syntax error's are raised for listcomps used as lvalues
+
+    >>> [y for y in (1,2)] = 10          # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+       ...
+    SyntaxError: ...
+
+    >>> [y for y in (1,2)] += 10         # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+       ...
+    SyntaxError: ...
+
+
+########### Tests borrowed from or inspired by test_generators.py ############
+
+Make a nested list comprehension that acts like range()
+
+    >>> def frange(n):
+    ...     return [i for i in xrange(n)]
+    >>> frange(10)
+    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+Same again, only as a lambda expression instead of a function definition
+
+    >>> lrange = lambda n:  [i for i in xrange(n)]
+    >>> lrange(10)
+    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+Generators can call other generators:
+
+    >>> def grange(n):
+    ...     for x in [i for i in xrange(n)]:
+    ...         yield x
+    >>> list(grange(5))
+    [0, 1, 2, 3, 4]
+
+
+Make sure that None is a valid return value
+
+    >>> [None for i in xrange(10)]
+    [None, None, None, None, None, None, None, None, None, None]
+
+########### Tests for various scoping corner cases ############
+
+Return lambdas that use the iteration variable as a default argument
+
+    >>> items = [(lambda i=i: i) for i in range(5)]
+    >>> [x() for x in items]
+    [0, 1, 2, 3, 4]
+
+Same again, only this time as a closure variable
+
+    >>> items = [(lambda: i) for i in range(5)]
+    >>> [x() for x in items]
+    [4, 4, 4, 4, 4]
+
+Another way to test that the iteration variable is local to the list comp
+
+    >>> items = [(lambda: i) for i in range(5)]
+    >>> i = 20
+    >>> [x() for x in items]
+    [4, 4, 4, 4, 4]
+
+And confirm that a closure can jump over the list comp scope
+
+    >>> items = [(lambda: y) for i in range(5)]
+    >>> y = 2
+    >>> [x() for x in items]
+    [2, 2, 2, 2, 2]
+
+We also repeat each of the above scoping tests inside a function
+
+    >>> def test_func():
+    ...     items = [(lambda i=i: i) for i in range(5)]
+    ...     return [x() for x in items]
+    >>> test_func()
+    [0, 1, 2, 3, 4]
+
+    >>> def test_func():
+    ...     items = [(lambda: i) for i in range(5)]
+    ...     return [x() for x in items]
+    >>> test_func()
+    [4, 4, 4, 4, 4]
+
+    >>> def test_func():
+    ...     items = [(lambda: i) for i in range(5)]
+    ...     i = 20
+    ...     return [x() for x in items]
+    >>> test_func()
+    [4, 4, 4, 4, 4]
+
+    >>> def test_func():
+    ...     items = [(lambda: y) for i in range(5)]
+    ...     y = 2
+    ...     return [x() for x in items]
+    >>> test_func()
+    [2, 2, 2, 2, 2]
+
+"""
+
+
+__test__ = {'doctests' : doctests}
+
+def test_main(verbose=None):
+    import sys
+    from test import test_support
+    from test import test_listcomps
+    test_support.run_doctest(test_listcomps, verbose)
+
+    # verify reference counting
+    if verbose and hasattr(sys, "gettotalrefcount"):
+        import gc
+        counts = [None] * 5
+        for i in xrange(len(counts)):
+            test_support.run_doctest(test_genexps, verbose)
+            gc.collect()
+            counts[i] = sys.gettotalrefcount()
+        print(counts)
+
+if __name__ == "__main__":
+    test_main(verbose=True)