Issue #2335: Backport set literals syntax from Python 3.x.

9 files changed, 80 insertions, 28 deletions

diff --git a/Lib/compiler/ast.py b/Lib/compiler/ast.py
index f923077..f47434c 100644
--- a/Lib/compiler/ast.py
+++ b/Lib/compiler/ast.py
@@ -1107,6 +1107,22 @@ class RightShift(Node):
     def __repr__(self):
         return "RightShift((%s, %s))" % (repr(self.left), repr(self.right))
 
+class Set(Node):
+    def __init__(self, nodes, lineno=None):
+        self.nodes = nodes
+        self.lineno = lineno
+
+    def getChildren(self):
+        return tuple(flatten(self.nodes))
+
+    def getChildNodes(self):
+        nodelist = []
+        nodelist.extend(flatten_nodes(self.nodes))
+        return tuple(nodelist)
+
+    def __repr__(self):
+        return "Set(%s)" % (repr(self.nodes),)
+
 class Slice(Node):
     def __init__(self, expr, flags, lower, upper, lineno=None):
         self.expr = expr
diff --git a/Lib/compiler/pyassem.py b/Lib/compiler/pyassem.py
index be0255d..88510de 100644
--- a/Lib/compiler/pyassem.py
+++ b/Lib/compiler/pyassem.py
@@ -734,6 +734,8 @@ class StackDepthTracker:
         return -count+1
     def BUILD_LIST(self, count):
         return -count+1
+    def BUILD_SET(self, count):
+        return -count+1
     def CALL_FUNCTION(self, argc):
         hi, lo = divmod(argc, 256)
         return -(lo + hi * 2)
diff --git a/Lib/compiler/pycodegen.py b/Lib/compiler/pycodegen.py
index 960c4fc..bef9c70 100644
--- a/Lib/compiler/pycodegen.py
+++ b/Lib/compiler/pycodegen.py
@@ -1215,6 +1215,12 @@ class CodeGenerator:
             self.visit(elt)
         self.emit('BUILD_LIST', len(node.nodes))
 
+    def visitSet(self, node):
+        self.set_lineno(node)
+        for elt in node.nodes:
+            self.visit(elt)
+        self.emit('BUILD_SET', len(node.nodes))
+
     def visitSliceobj(self, node):
         for child in node.nodes:
             self.visit(child)
diff --git a/Lib/compiler/transformer.py b/Lib/compiler/transformer.py
index 2a156d3..816f13b 100644
--- a/Lib/compiler/transformer.py
+++ b/Lib/compiler/transformer.py
@@ -749,7 +749,7 @@ class Transformer:
     def atom_lbrace(self, nodelist):
         if nodelist[1][0] == token.RBRACE:
             return Dict((), lineno=nodelist[0][2])
-        return self.com_dictmaker(nodelist[1])
+        return self.com_dictorsetmaker(nodelist[1])
 
     def atom_backquote(self, nodelist):
         return Backquote(self.com_node(nodelist[1]))
@@ -1197,13 +1197,21 @@ class Transformer:
             assert node[0] == symbol.gen_iter
             return node[1]
 
-    def com_dictmaker(self, nodelist):
-        # dictmaker: test ':' test (',' test ':' value)* [',']
-        items = []
-        for i in range(1, len(nodelist), 4):
-            items.append((self.com_node(nodelist[i]),
-                          self.com_node(nodelist[i+2])))
-        return Dict(items, lineno=items[0][0].lineno)
+    def com_dictorsetmaker(self, nodelist):
+        # dictorsetmaker: ( (test ':' test (',' test ':' test)* [',']) |
+        #                   (test (',' test)* [',']) )
+        assert nodelist[0] == symbol.dictorsetmaker
+        if len(nodelist) == 2 or nodelist[2][0] == token.COMMA:
+            items = []
+            for i in range(1, len(nodelist), 2):
+                items.append(self.com_node(nodelist[i]))
+            return Set(items, lineno=items[0].lineno)
+        else:
+            items = []
+            for i in range(1, len(nodelist), 4):
+                items.append((self.com_node(nodelist[i]),
+                              self.com_node(nodelist[i+2])))
+            return Dict(items, lineno=items[0][0].lineno)
 
     def com_apply_trailer(self, primaryNode, nodelist):
         t = nodelist[1][0]
diff --git a/Lib/opcode.py b/Lib/opcode.py
index 7c3962d..f11e475 100644
--- a/Lib/opcode.py
+++ b/Lib/opcode.py
@@ -138,13 +138,13 @@ hasconst.append(100)
 name_op('LOAD_NAME', 101)       # Index in name list
 def_op('BUILD_TUPLE', 102)      # Number of tuple items
 def_op('BUILD_LIST', 103)       # Number of list items
-def_op('BUILD_MAP', 104)        # Number of dict entries (upto 255)
-name_op('LOAD_ATTR', 105)       # Index in name list
-def_op('COMPARE_OP', 106)       # Comparison operator
-hascompare.append(106)
-name_op('IMPORT_NAME', 107)     # Index in name list
-name_op('IMPORT_FROM', 108)     # Index in name list
-
+def_op('BUILD_SET', 104)        # Number of set items
+def_op('BUILD_MAP', 105)        # Number of dict entries (upto 255)
+name_op('LOAD_ATTR', 106)       # Index in name list
+def_op('COMPARE_OP', 107)       # Comparison operator
+hascompare.append(107)
+name_op('IMPORT_NAME', 108)     # Index in name list
+name_op('IMPORT_FROM', 109)     # Index in name list
 jrel_op('JUMP_FORWARD', 110)    # Number of bytes to skip
 jabs_op('JUMP_IF_FALSE_OR_POP', 111) # Target byte offset from beginning of code
 jabs_op('JUMP_IF_TRUE_OR_POP', 112)  # ""
diff --git a/Lib/symbol.py b/Lib/symbol.py
index c360e39..c0bb145 100755
--- a/Lib/symbol.py
+++ b/Lib/symbol.py
@@ -83,18 +83,19 @@ sliceop = 325
 exprlist = 326
 testlist = 327
 dictmaker = 328
-classdef = 329
-arglist = 330
-argument = 331
-list_iter = 332
-list_for = 333
-list_if = 334
-gen_iter = 335
-gen_for = 336
-gen_if = 337
-testlist1 = 338
-encoding_decl = 339
-yield_expr = 340
+dictorsetmaker = 329
+classdef = 330
+arglist = 331
+argument = 332
+list_iter = 333
+list_for = 334
+list_if = 335
+gen_iter = 336
+gen_for = 337
+gen_if = 338
+testlist1 = 339
+encoding_decl = 340
+yield_expr = 341
 #--end constants--
 
 sym_name = {}
diff --git a/Lib/test/test_compiler.py b/Lib/test/test_compiler.py
index 24930f8..8d4a3a99 100644
--- a/Lib/test/test_compiler.py
+++ b/Lib/test/test_compiler.py
@@ -248,6 +248,7 @@ l[0]
 l[3:4]
 d = {'a': 2}
 d = {}
+s = {1}
 t = ()
 t = (1, 2)
 l = []
diff --git a/Lib/test/test_grammar.py b/Lib/test/test_grammar.py
index f144ae7..4713d1a 100644
--- a/Lib/test/test_grammar.py
+++ b/Lib/test/test_grammar.py
@@ -749,7 +749,7 @@ hello world
 
     def testAtoms(self):
         ### atom: '(' [testlist] ')' | '[' [testlist] ']' | '{' [dictmaker] '}' | '`' testlist '`' | NAME | NUMBER | STRING
-        ### dictmaker: test ':' test (',' test ':' test)* [',']
+        ### dictorsetmaker: (test ':' test (',' test ':' test)* [',']) | (test (',' test)* [','])
 
         x = (1)
         x = (1 or 2 or 3)
@@ -769,6 +769,11 @@ hello world
         x = {'one': 1, 'two': 2,}
         x = {'one': 1, 'two': 2, 'three': 3, 'four': 4, 'five': 5, 'six': 6}
 
+        x = {'one'}
+        x = {'one', 1,}
+        x = {'one', 'two', 'three'}
+        x = {2, 3, 4,}
+
         x = `x`
         x = `1 or 2 or 3`
         self.assertEqual(`1,2`, '(1, 2)')
diff --git a/Lib/test/test_parser.py b/Lib/test/test_parser.py
index a7f8fc2..03803d9 100644
--- a/Lib/test/test_parser.py
+++ b/Lib/test/test_parser.py
@@ -59,7 +59,20 @@ class RoundtripLegalSyntaxTestCase(unittest.TestCase):
 
     def test_expressions(self):
         self.check_expr("foo(1)")
+        self.check_expr("{1:1}")
+        self.check_expr("{1:1, 2:2, 3:3}")
+        self.check_expr("{1:1, 2:2, 3:3,}")
+        self.check_expr("{1}")
+        self.check_expr("{1, 2, 3}")
+        self.check_expr("{1, 2, 3,}")
+        self.check_expr("[]")
+        self.check_expr("[1]")
         self.check_expr("[1, 2, 3]")
+        self.check_expr("[1, 2, 3,]")
+        self.check_expr("()")
+        self.check_expr("(1,)")
+        self.check_expr("(1, 2, 3)")
+        self.check_expr("(1, 2, 3,)")
         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]")