Issue #2333: Backport set and dict comprehensions syntax.
diff --git a/Lib/test/test_compiler.py b/Lib/test/test_compiler.py
index 8d4a3a99..b54894d 100644
--- a/Lib/test/test_compiler.py
+++ b/Lib/test/test_compiler.py
@@ -140,6 +140,36 @@
                              'eval')
         self.assertEquals(eval(c), [(0, 3), (1, 3), (2, 3)])
 
+    def testSetLiteral(self):
+        c = compiler.compile('{1, 2, 3}', '<string>', 'eval')
+        self.assertEquals(eval(c), {1,2,3})
+        c = compiler.compile('{1, 2, 3,}', '<string>', 'eval')
+        self.assertEquals(eval(c), {1,2,3})
+
+    def testDictLiteral(self):
+        c = compiler.compile('{1:2, 2:3, 3:4}', '<string>', 'eval')
+        self.assertEquals(eval(c), {1:2, 2:3, 3:4})
+        c = compiler.compile('{1:2, 2:3, 3:4,}', '<string>', 'eval')
+        self.assertEquals(eval(c), {1:2, 2:3, 3:4})
+
+    def testSetComp(self):
+        c = compiler.compile('{x for x in range(1, 4)}', '<string>', 'eval')
+        self.assertEquals(eval(c), {1, 2, 3})
+        c = compiler.compile('{x * y for x in range(3) if x != 0'
+                             '       for y in range(4) if y != 0}',
+                             '<string>',
+                             'eval')
+        self.assertEquals(eval(c), {1, 2, 3, 4, 6})
+
+    def testDictComp(self):
+        c = compiler.compile('{x:x+1 for x in range(1, 4)}', '<string>', 'eval')
+        self.assertEquals(eval(c), {1:2, 2:3, 3:4})
+        c = compiler.compile('{(x, y) : y for x in range(2) if x != 0'
+                             '            for y in range(3) if y != 0}',
+                             '<string>',
+                             'eval')
+        self.assertEquals(eval(c), {(1, 2): 2, (1, 1): 1})
+
     def testWith(self):
         # SF bug 1638243
         c = compiler.compile('from __future__ import with_statement\n'
@@ -248,6 +278,8 @@
 l[3:4]
 d = {'a': 2}
 d = {}
+d = {x: y for x, y in zip(range(5), range(5,10))}
+s = {x for x in range(10)}
 s = {1}
 t = ()
 t = (1, 2)
diff --git a/Lib/test/test_dictcomps.py b/Lib/test/test_dictcomps.py
new file mode 100644
index 0000000..9af9e48
--- /dev/null
+++ b/Lib/test/test_dictcomps.py
@@ -0,0 +1,54 @@
+
+doctests = """
+
+    >>> k = "old value"
+    >>> { k: None for k in range(10) }
+    {0: None, 1: None, 2: None, 3: None, 4: None, 5: None, 6: None, 7: None, 8: None, 9: None}
+    >>> k
+    'old value'
+
+    >>> { k: k+10 for k in range(10) }
+    {0: 10, 1: 11, 2: 12, 3: 13, 4: 14, 5: 15, 6: 16, 7: 17, 8: 18, 9: 19}
+
+    >>> g = "Global variable"
+    >>> { k: g for k in range(10) }
+    {0: 'Global variable', 1: 'Global variable', 2: 'Global variable', 3: 'Global variable', 4: 'Global variable', 5: 'Global variable', 6: 'Global variable', 7: 'Global variable', 8: 'Global variable', 9: 'Global variable'}
+
+    >>> { k: v for k in range(10) for v in range(10) if k == v }
+    {0: 0, 1: 1, 2: 2, 3: 3, 4: 4, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9}
+
+    >>> { k: v for v in range(10) for k in range(v*9, v*10) }
+    {9: 1, 18: 2, 19: 2, 27: 3, 28: 3, 29: 3, 36: 4, 37: 4, 38: 4, 39: 4, 45: 5, 46: 5, 47: 5, 48: 5, 49: 5, 54: 6, 55: 6, 56: 6, 57: 6, 58: 6, 59: 6, 63: 7, 64: 7, 65: 7, 66: 7, 67: 7, 68: 7, 69: 7, 72: 8, 73: 8, 74: 8, 75: 8, 76: 8, 77: 8, 78: 8, 79: 8, 81: 9, 82: 9, 83: 9, 84: 9, 85: 9, 86: 9, 87: 9, 88: 9, 89: 9}
+
+    >>> { x: y for y, x in ((1, 2), (3, 4)) } = 5 # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+       ...
+    SyntaxError: ...
+
+    >>> { x: y for y, x in ((1, 2), (3, 4)) } += 5 # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+       ...
+    SyntaxError: ...
+
+"""
+
+__test__ = {'doctests' : doctests}
+
+def test_main(verbose=None):
+    import sys
+    from test import test_support
+    from test import test_dictcomps
+    test_support.run_doctest(test_dictcomps, verbose)
+
+    # verify reference counting
+    if verbose and hasattr(sys, "gettotalrefcount"):
+        import gc
+        counts = [None] * 5
+        for i in range(len(counts)):
+            test_support.run_doctest(test_dictcomps, verbose)
+            gc.collect()
+            counts[i] = sys.gettotalrefcount()
+        print(counts)
+
+if __name__ == "__main__":
+    test_main(verbose=True)
diff --git a/Lib/test/test_grammar.py b/Lib/test/test_grammar.py
index 4713d1a..12039e7 100644
--- a/Lib/test/test_grammar.py
+++ b/Lib/test/test_grammar.py
@@ -808,6 +808,13 @@
             pass
         self.assertEqual(G.decorated, True)
 
+    def testDictcomps(self):
+        # dictorsetmaker: ( (test ':' test (comp_for |
+        #                                   (',' test ':' test)* [','])) |
+        #                   (test (comp_for | (',' test)* [','])) )
+        nums = [1, 2, 3]
+        self.assertEqual({i:i+1 for i in nums}, {1: 2, 2: 3, 3: 4})
+
     def testListcomps(self):
         # list comprehension tests
         nums = [1, 2, 3, 4, 5]
diff --git a/Lib/test/test_parser.py b/Lib/test/test_parser.py
index 03803d9..6ae9975 100644
--- a/Lib/test/test_parser.py
+++ b/Lib/test/test_parser.py
@@ -76,9 +76,20 @@
         self.check_expr("[x**3 for x in range(20)]")
         self.check_expr("[x**3 for x in range(20) if x % 3]")
         self.check_expr("[x**3 for x in range(20) if x % 2 if x % 3]")
+        self.check_expr("[x+y for x in range(30) for y in range(20) if x % 2 if y % 3]")
+        #self.check_expr("[x for x in lambda: True, lambda: False if x()]")
         self.check_expr("list(x**3 for x in range(20))")
         self.check_expr("list(x**3 for x in range(20) if x % 3)")
         self.check_expr("list(x**3 for x in range(20) if x % 2 if x % 3)")
+        self.check_expr("list(x+y for x in range(30) for y in range(20) if x % 2 if y % 3)")
+        self.check_expr("{x**3 for x in range(30)}")
+        self.check_expr("{x**3 for x in range(30) if x % 3}")
+        self.check_expr("{x**3 for x in range(30) if x % 2 if x % 3}")
+        self.check_expr("{x+y for x in range(30) for y in range(20) if x % 2 if y % 3}")
+        self.check_expr("{x**3: y**2 for x, y in zip(range(30), range(30))}")
+        self.check_expr("{x**3: y**2 for x, y in zip(range(30), range(30)) if x % 3}")
+        self.check_expr("{x**3: y**2 for x, y in zip(range(30), range(30)) if x % 3 if y % 3}")
+        self.check_expr("{x:y for x in range(30) for y in range(20) if x % 2 if y % 3}")
         self.check_expr("foo(*args)")
         self.check_expr("foo(*args, **kw)")
         self.check_expr("foo(**kw)")
@@ -107,6 +118,7 @@
         self.check_expr("lambda foo=bar, blaz=blat+2, **z: 0")
         self.check_expr("lambda foo=bar, blaz=blat+2, *y, **z: 0")
         self.check_expr("lambda x, *y, **z: 0")
+        self.check_expr("lambda x: 5 if x else 2")
         self.check_expr("(x for x in range(10))")
         self.check_expr("foo(x for x in range(10))")
 
diff --git a/Lib/test/test_setcomps.py b/Lib/test/test_setcomps.py
new file mode 100644
index 0000000..db5e6f7
--- /dev/null
+++ b/Lib/test/test_setcomps.py
@@ -0,0 +1,151 @@
+doctests = """
+########### Tests mostly copied from test_listcomps.py ############
+
+Test simple loop with conditional
+
+    >>> sum({i*i for i in range(100) if i&1 == 1})
+    166650
+
+Test simple case
+
+    >>> {2*y + x + 1 for x in (0,) for y in (1,)}
+    set([3])
+
+Test simple nesting
+
+    >>> list(sorted({(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
+
+    >>> list(sorted({(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 setcomps 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: ...
+
+
+Make a nested set comprehension that acts like set(range())
+
+    >>> def srange(n):
+    ...     return {i for i in range(n)}
+    >>> list(sorted(srange(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 range(n)}
+    >>> list(sorted(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 range(n)}:
+    ...         yield x
+    >>> list(sorted(grange(5)))
+    [0, 1, 2, 3, 4]
+
+
+Make sure that None is a valid return value
+
+    >>> {None for i in range(10)}
+    set([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} == set(range(5))
+    True
+
+Same again, only this time as a closure variable
+
+    >>> items = {(lambda: i) for i in range(5)}
+    >>> {x() for x in items}
+    set([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}
+    set([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}
+    set([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() == set(range(5))
+    True
+
+    >>> def test_func():
+    ...     items = {(lambda: i) for i in range(5)}
+    ...     return {x() for x in items}
+    >>> test_func()
+    set([4])
+
+    >>> def test_func():
+    ...     items = {(lambda: i) for i in range(5)}
+    ...     i = 20
+    ...     return {x() for x in items}
+    >>> test_func()
+    set([4])
+
+    >>> def test_func():
+    ...     items = {(lambda: y) for i in range(5)}
+    ...     y = 2
+    ...     return {x() for x in items}
+    >>> test_func()
+    set([2])
+
+"""
+
+
+__test__ = {'doctests' : doctests}
+
+def test_main(verbose=None):
+    import sys
+    from test import test_support
+    from test import test_setcomps
+    test_support.run_doctest(test_setcomps, verbose)
+
+    # verify reference counting
+    if verbose and hasattr(sys, "gettotalrefcount"):
+        import gc
+        counts = [None] * 5
+        for i in range(len(counts)):
+            test_support.run_doctest(test_setcomps, verbose)
+            gc.collect()
+            counts[i] = sys.gettotalrefcount()
+        print(counts)
+
+if __name__ == "__main__":
+    test_main(verbose=True)