Jiwon Seo's PEP 3102 implementation.

See SF#1549670.
The compiler package has not yet been updated.

Grammar/Grammar

@@ -24,7 +24,7 @@ decorators: decorator+
 funcdef: [decorators] 'def' NAME parameters ':' suite
 parameters: '(' [varargslist] ')'
 varargslist: ((fpdef ['=' test] ',')*
-              ('*' NAME [',' '**' NAME] | '**' NAME) |
+              ('*' [NAME] (',' NAME ['=' test])*  [',' '**' NAME] | '**' NAME) |
               fpdef ['=' test] (',' fpdef ['=' test])* [','])
 fpdef: NAME | '(' fplist ')'
 fplist: fpdef (',' fpdef)* [',']

Include/Python-ast.h

@@ -328,8 +328,10 @@ struct _excepthandler {
 struct _arguments {
         asdl_seq *args;
         identifier vararg;
+        asdl_seq *kwonlyargs;
         identifier kwarg;
         asdl_seq *defaults;
+        asdl_seq *kw_defaults;
 };
 
 struct _keyword {
@@ -427,8 +429,9 @@ comprehension_ty comprehension(expr_ty target, expr_ty iter, asdl_seq * ifs,
                                PyArena *arena);
 excepthandler_ty excepthandler(expr_ty type, expr_ty name, asdl_seq * body, int
                                lineno, int col_offset, PyArena *arena);
-arguments_ty arguments(asdl_seq * args, identifier vararg, identifier kwarg,
+arguments_ty arguments(asdl_seq * args, identifier vararg, asdl_seq *
-                       asdl_seq * defaults, PyArena *arena);
+                       kwonlyargs, identifier kwarg, asdl_seq * defaults,
+                       asdl_seq * kw_defaults, PyArena *arena);
 keyword_ty keyword(identifier arg, expr_ty value, PyArena *arena);
 alias_ty alias(identifier name, identifier asname, PyArena *arena);
 

Include/code.h

@@ -10,6 +10,7 @@ extern "C" {
 typedef struct {
     PyObject_HEAD
     int co_argcount;		/* #arguments, except *args */
+    int co_kwonlyargcount;	/* #keyword only arguments */
     int co_nlocals;		/* #local variables */
     int co_stacksize;		/* #entries needed for evaluation stack */
     int co_flags;		/* CO_..., see below */
@@ -63,8 +64,9 @@ PyAPI_DATA(PyTypeObject) PyCode_Type;
 
 /* Public interface */
 PyAPI_FUNC(PyCodeObject *) PyCode_New(
-	int, int, int, int, PyObject *, PyObject *, PyObject *, PyObject *,
+	int, int, int, int, int, PyObject *, PyObject *,
-	PyObject *, PyObject *, PyObject *, PyObject *, int, PyObject *); 
+	PyObject *, PyObject *, PyObject *, PyObject *,
+	PyObject *, PyObject *, int, PyObject *); 
         /* same as struct above */
 PyAPI_FUNC(int) PyCode_Addr2Line(PyCodeObject *, int);
 

Include/eval.h

@@ -15,7 +15,7 @@ PyAPI_FUNC(PyObject *) PyEval_EvalCodeEx(PyCodeObject *co,
 					PyObject **args, int argc,
 					PyObject **kwds, int kwdc,
 					PyObject **defs, int defc,
-					PyObject *closure);
+					PyObject *kwdefs, PyObject *closure);
 
 PyAPI_FUNC(PyObject *) _PyEval_CallTracing(PyObject *func, PyObject *args);
 

Include/funcobject.h

@@ -23,6 +23,7 @@ typedef struct {
     PyObject *func_code;	/* A code object */
     PyObject *func_globals;	/* A dictionary (other mappings won't do) */
     PyObject *func_defaults;	/* NULL or a tuple */
+    PyObject *func_kwdefaults;	/* NULL or a dict */
     PyObject *func_closure;	/* NULL or a tuple of cell objects */
     PyObject *func_doc;		/* The __doc__ attribute, can be anything */
     PyObject *func_name;	/* The __name__ attribute, a string object */
@@ -47,6 +48,8 @@ PyAPI_FUNC(PyObject *) PyFunction_GetGlobals(PyObject *);
 PyAPI_FUNC(PyObject *) PyFunction_GetModule(PyObject *);
 PyAPI_FUNC(PyObject *) PyFunction_GetDefaults(PyObject *);
 PyAPI_FUNC(int) PyFunction_SetDefaults(PyObject *, PyObject *);
+PyAPI_FUNC(PyObject *) PyFunction_GetKwDefaults(PyObject *);
+PyAPI_FUNC(int) PyFunction_SetKwDefaults(PyObject *, PyObject *);
 PyAPI_FUNC(PyObject *) PyFunction_GetClosure(PyObject *);
 PyAPI_FUNC(int) PyFunction_SetClosure(PyObject *, PyObject *);
 
@@ -60,6 +63,8 @@ PyAPI_FUNC(int) PyFunction_SetClosure(PyObject *, PyObject *);
 	(((PyFunctionObject *)func) -> func_module)
 #define PyFunction_GET_DEFAULTS(func) \
 	(((PyFunctionObject *)func) -> func_defaults)
+#define PyFunction_GET_KW_DEFAULTS(func) \
+	(((PyFunctionObject *)func) -> func_kwdefaults)
 #define PyFunction_GET_CLOSURE(func) \
 	(((PyFunctionObject *)func) -> func_closure)
 

Lib/compiler/ast.py

@@ -487,11 +487,12 @@ class From(Node):
         return "From(%s, %s, %s)" % (repr(self.modname), repr(self.names), repr(self.level))
 
 class Function(Node):
-    def __init__(self, decorators, name, argnames, defaults, flags, doc, code, lineno=None):
+    def __init__(self, decorators, name, argnames, defaults, kwonlyargs, flags, doc, code, lineno=None):
         self.decorators = decorators
         self.name = name
         self.argnames = argnames
         self.defaults = defaults
+        self.kwonlyargs = kwonlyargs
         self.flags = flags
         self.doc = doc
         self.code = code
@@ -509,6 +510,7 @@ class Function(Node):
         children.append(self.name)
         children.append(self.argnames)
         children.extend(flatten(self.defaults))
+        children.append(self.kwonlyargs)
         children.append(self.flags)
         children.append(self.doc)
         children.append(self.code)
@@ -523,7 +525,7 @@ class Function(Node):
         return tuple(nodelist)
 
     def __repr__(self):
-        return "Function(%s, %s, %s, %s, %s, %s, %s)" % (repr(self.decorators), repr(self.name), repr(self.argnames), repr(self.defaults), repr(self.flags), repr(self.doc), repr(self.code))
+        return "Function(%s, %s, %s, %s, %s, %s, %s, %s)" % (repr(self.decorators), repr(self.name), repr(self.argnames), repr(self.defaults), repr(self.kwonlyargs), repr(self.flags), repr(self.doc), repr(self.code))
 
 class GenExpr(Node):
     def __init__(self, code, lineno=None):
@@ -531,6 +533,7 @@ class GenExpr(Node):
         self.lineno = lineno
         self.argnames = ['.0']
         self.varargs = self.kwargs = None
+        self.kwonlyargs = ()
 
 
     def getChildren(self):
@@ -713,9 +716,10 @@ class Keyword(Node):
         return "Keyword(%s, %s)" % (repr(self.name), repr(self.expr))
 
 class Lambda(Node):
-    def __init__(self, argnames, defaults, flags, code, lineno=None):
+    def __init__(self, argnames, defaults, kwonlyargs, flags, code, lineno=None):
         self.argnames = argnames
         self.defaults = defaults
+        self.kwonlyargs = kwonlyargs
         self.flags = flags
         self.code = code
         self.lineno = lineno
@@ -730,6 +734,7 @@ class Lambda(Node):
         children = []
         children.append(self.argnames)
         children.extend(flatten(self.defaults))
+        children.append(self.kwonlyargs)
         children.append(self.flags)
         children.append(self.code)
         return tuple(children)
@@ -741,7 +746,7 @@ class Lambda(Node):
         return tuple(nodelist)
 
     def __repr__(self):
-        return "Lambda(%s, %s, %s, %s)" % (repr(self.argnames), repr(self.defaults), repr(self.flags), repr(self.code))
+        return "Lambda(%s, %s, %s, %s, %s)" % (repr(self.argnames), repr(self.defaults), repr(self.kwonlyargs), repr(self.flags), repr(self.code))
 
 class LeftShift(Node):
     def __init__(self, (left, right), lineno=None):

Lib/compiler/pyassem.py

@@ -313,13 +313,15 @@ DONE = "DONE"
 class PyFlowGraph(FlowGraph):
     super_init = FlowGraph.__init__
 
-    def __init__(self, name, filename, args=(), optimized=0, klass=None):
+    def __init__(self, name, filename,
+                 args=(), kwonlyargs={}, optimized=0, klass=None):
         self.super_init()
         self.name = name
         self.filename = filename
         self.docstring = None
         self.args = args # XXX
         self.argcount = getArgCount(args)
+        self.kwonlyargs = kwonlyargs
         self.klass = klass
         if optimized:
             self.flags = CO_OPTIMIZED | CO_NEWLOCALS
@@ -595,7 +597,9 @@ class PyFlowGraph(FlowGraph):
         argcount = self.argcount
         if self.flags & CO_VARKEYWORDS:
             argcount = argcount - 1
-        return new.code(argcount, nlocals, self.stacksize, self.flags,
+        kwonlyargcount = len(self.kwonlyargs)
+        return new.code(argcount, kwonlyargcount,
+                        nlocals, self.stacksize, self.flags,
                         self.lnotab.getCode(), self.getConsts(),
                         tuple(self.names), tuple(self.varnames),
                         self.filename, self.name, self.lnotab.firstline,
@@ -804,7 +808,8 @@ class StackDepthTracker:
     def CALL_FUNCTION_VAR_KW(self, argc):
         return self.CALL_FUNCTION(argc)-2
     def MAKE_FUNCTION(self, argc):
-        return -argc
+        hi, lo = divmod(argc, 256)
+        return -(lo + hi * 2)
     def MAKE_CLOSURE(self, argc):
         # XXX need to account for free variables too!
         return -argc

Lib/compiler/pycodegen.py

@@ -378,6 +378,12 @@ class CodeGenerator:
         walk(node.code, gen)
         gen.finish()
         self.set_lineno(node)
+        for keyword in node.kwonlyargs:
+            default = keyword.expr
+            if isinstance(default, ast.EmptyNode):
+                continue
+            self.emit('LOAD_CONST', keyword.name)
+            self.visit(default)
         for default in node.defaults:
             self.visit(default)
         self._makeClosure(gen, len(node.defaults))
@@ -1320,7 +1326,9 @@ class AbstractFunctionCode:
             name = func.name
 
         args, hasTupleArg = generateArgList(func.argnames)
+        kwonlyargs = generateKwonlyArgList(func.kwonlyargs)
         self.graph = pyassem.PyFlowGraph(name, func.filename, args,
+                                         kwonlyargs=kwonlyargs,
                                          optimized=1)
         self.isLambda = isLambda
         self.super_init()
@@ -1456,6 +1464,13 @@ def generateArgList(arglist):
             raise ValueError, "unexpect argument type:", elt
     return args + extra, count
 
+def generateKwonlyArgList(keywordOnlyArgs):
+    kwonlyargs = {}
+    for elt in keywordOnlyArgs:
+        assert isinstance(elt, ast.Keyword)
+        kwonlyargs[elt.name] = elt.expr
+    return kwonlyargs
+    
 def findOp(node):
     """Find the op (DELETE, LOAD, STORE) in an AssTuple tree"""
     v = OpFinder()

Lib/compiler/transformer.py

@@ -250,9 +250,9 @@ class Transformer:
         args = nodelist[-3][2]
 
         if args[0] == symbol.varargslist:
-            names, defaults, flags = self.com_arglist(args[1:])
+            names, defaults, kwonlyargs, flags = self.com_arglist(args[1:])
         else:
-            names = defaults = ()
+            names = defaults = kwonlyargs = ()
             flags = 0
         doc = self.get_docstring(nodelist[-1])
 
@@ -263,21 +263,23 @@ class Transformer:
             assert isinstance(code, Stmt)
             assert isinstance(code.nodes[0], Discard)
             del code.nodes[0]
-        return Function(decorators, name, names, defaults, flags, doc, code,
+        return Function(decorators, name, names, defaults,
-                     lineno=lineno)
+                        kwonlyargs, flags, doc, code, lineno=lineno)
 
     def lambdef(self, nodelist):
         # lambdef: 'lambda' [varargslist] ':' test
         if nodelist[2][0] == symbol.varargslist:
-            names, defaults, flags = self.com_arglist(nodelist[2][1:])
+            names, defaults, kwonlyargs, flags = \
+                                self.com_arglist(nodelist[2][1:])
         else:
-            names = defaults = ()
+            names = defaults = kwonlyargs = ()
             flags = 0
 
         # code for lambda
         code = self.com_node(nodelist[-1])
 
-        return Lambda(names, defaults, flags, code, lineno=nodelist[1][2])
+        return Lambda(names, defaults, kwonlyargs,
+                      flags, code, lineno=nodelist[1][2])
     old_lambdef = lambdef
 
     def classdef(self, nodelist):
@@ -783,13 +785,37 @@ class Transformer:
         # ('const', xxxx)) Nodes)
         return Discard(Const(None))
 
+    def keywordonlyargs(self, nodelist):
+        # (',' NAME ['=' test])*
+        #      ^^^
+        # ------+
+        kwonlyargs = []
+        i = 0
+        while i < len(nodelist):
+            default = EmptyNode()
+            node = nodelist[i]
+            #assert node[0] == token.COMMA
+            #node = nodelist[i+1]
+            if i+1 < len(nodelist) and nodelist[i+1][0] == token.EQUAL:
+                assert i+2 < len(nodelist)
+                default = self.com_node(nodelist[i+2])
+                i += 2
+            if node[0] == token.DOUBLESTAR:
+                return kwonlyargs, i
+            elif node[0] == token.NAME:
+                kwonlyargs.append(Keyword(node[1], default, lineno=node[2]))
+                i += 2
+        return kwonlyargs, i
+        
     def com_arglist(self, nodelist):
         # varargslist:
-        #     (fpdef ['=' test] ',')* ('*' NAME [',' '**' NAME] | '**' NAME)
+        #     (fpdef ['=' test] ',')*
+        #      ('*' [NAME] (',' NAME '=' test)* [',' '**' NAME] | '**' NAME)
         #      | fpdef ['=' test] (',' fpdef ['=' test])* [',']
         # fpdef: NAME | '(' fplist ')'
         # fplist: fpdef (',' fpdef)* [',']
         names = []
+        kwonlyargs = []
         defaults = []
         flags = 0
 
@@ -799,10 +825,22 @@ class Transformer:
             if node[0] == token.STAR or node[0] == token.DOUBLESTAR:
                 if node[0] == token.STAR:
                     node = nodelist[i+1]
-                    if node[0] == token.NAME:
+                    if node[0] == token.NAME: # vararg
                         names.append(node[1])
                         flags = flags | CO_VARARGS
                         i = i + 3
+                    else: # no vararg
+                        assert node[0] == token.COMMA
+                        i += 1
+                    #elif node[0] == token.COMMA:
+                    #    i += 1
+                    #    kwonlyargs, skip = self.keywordonlyargs(nodelist[i:])
+                    #    i += skip
+                    if nodelist[i][0] == token.NAME:
+                        kwonlyargs, skip = self.keywordonlyargs(nodelist[i:])
+                        i += skip
+
+                print "kwonlyargs:", kwonlyargs
 
                 if i < len(nodelist):
                     # should be DOUBLESTAR
@@ -831,7 +869,8 @@ class Transformer:
             # skip the comma
             i = i + 1
 
-        return names, defaults, flags
+        print "names:", names, "defaults:", defaults, "kwonlyargs:", kwonlyargs, "flags:", flags
+        return names, defaults, kwonlyargs, flags
 
     def com_fpdef(self, node):
         # fpdef: NAME | '(' fplist ')'

Lib/test/output/test_extcall

@@ -9,9 +9,9 @@ test_extcall
 (1, 2, 3) {'a': 4, 'b': 5}
 (1, 2, 3, 4, 5) {'a': 6, 'b': 7}
 (1, 2, 3, 6, 7) {'a': 8, 'b': 9, 'x': 4, 'y': 5}
-TypeError: g() takes at least 1 argument (0 given)
+TypeError: g() takes at least 1 positional argument (0 given)
-TypeError: g() takes at least 1 argument (0 given)
+TypeError: g() takes at least 1 positional argument (0 given)
-TypeError: g() takes at least 1 argument (0 given)
+TypeError: g() takes at least 1 positional argument (0 given)
 1 () {}
 1 (2,) {}
 1 (2, 3) {}
@@ -35,24 +35,24 @@ dir() got multiple values for keyword argument 'b'
 3 512 True
 3
 3
-za () {} -> za() takes exactly 1 argument (0 given)
+za () {} -> za() takes exactly 1 positional argument (0 given)
 za () {'a': 'aa'} -> ok za aa B D E V a
 za () {'d': 'dd'} -> za() got an unexpected keyword argument 'd'
 za () {'a': 'aa', 'd': 'dd'} -> za() got an unexpected keyword argument 'd'
 za () {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> za() got an unexpected keyword argument 'b'
-za (1, 2) {} -> za() takes exactly 1 argument (2 given)
+za (1, 2) {} -> za() takes exactly 1 positional argument (2 given)
-za (1, 2) {'a': 'aa'} -> za() takes exactly 1 non-keyword argument (2 given)
+za (1, 2) {'a': 'aa'} -> za() takes exactly 1 non-keyword positional argument (2 given)
-za (1, 2) {'d': 'dd'} -> za() takes exactly 1 non-keyword argument (2 given)
+za (1, 2) {'d': 'dd'} -> za() takes exactly 1 non-keyword positional argument (2 given)
-za (1, 2) {'a': 'aa', 'd': 'dd'} -> za() takes exactly 1 non-keyword argument (2 given)
+za (1, 2) {'a': 'aa', 'd': 'dd'} -> za() takes exactly 1 non-keyword positional argument (2 given)
-za (1, 2) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> za() takes exactly 1 non-keyword argument (2 given)
+za (1, 2) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> za() takes exactly 1 non-keyword positional argument (2 given)
-za (1, 2, 3, 4, 5) {} -> za() takes exactly 1 argument (5 given)
+za (1, 2, 3, 4, 5) {} -> za() takes exactly 1 positional argument (5 given)
-za (1, 2, 3, 4, 5) {'a': 'aa'} -> za() takes exactly 1 non-keyword argument (5 given)
+za (1, 2, 3, 4, 5) {'a': 'aa'} -> za() takes exactly 1 non-keyword positional argument (5 given)
-za (1, 2, 3, 4, 5) {'d': 'dd'} -> za() takes exactly 1 non-keyword argument (5 given)
+za (1, 2, 3, 4, 5) {'d': 'dd'} -> za() takes exactly 1 non-keyword positional argument (5 given)
-za (1, 2, 3, 4, 5) {'a': 'aa', 'd': 'dd'} -> za() takes exactly 1 non-keyword argument (5 given)
+za (1, 2, 3, 4, 5) {'a': 'aa', 'd': 'dd'} -> za() takes exactly 1 non-keyword positional argument (5 given)
-za (1, 2, 3, 4, 5) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> za() takes exactly 1 non-keyword argument (5 given)
+za (1, 2, 3, 4, 5) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> za() takes exactly 1 non-keyword positional argument (5 given)
-zade () {} -> zade() takes at least 1 argument (0 given)
+zade () {} -> zade() takes at least 1 positional argument (0 given)
 zade () {'a': 'aa'} -> ok zade aa B d e V a
-zade () {'d': 'dd'} -> zade() takes at least 1 non-keyword argument (0 given)
+zade () {'d': 'dd'} -> zade() takes at least 1 non-keyword positional argument (0 given)
 zade () {'a': 'aa', 'd': 'dd'} -> ok zade aa B dd e V d
 zade () {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> zade() got an unexpected keyword argument 'b'
 zade (1, 2) {} -> ok zade 1 B 2 e V e
@@ -60,30 +60,30 @@ zade (1, 2) {'a': 'aa'} -> zade() got multiple values for keyword argument 'a'
 zade (1, 2) {'d': 'dd'} -> zade() got multiple values for keyword argument 'd'
 zade (1, 2) {'a': 'aa', 'd': 'dd'} -> zade() got multiple values for keyword argument 'a'
 zade (1, 2) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> zade() got multiple values for keyword argument 'a'
-zade (1, 2, 3, 4, 5) {} -> zade() takes at most 3 arguments (5 given)
+zade (1, 2, 3, 4, 5) {} -> zade() takes at most 3 positional arguments (5 given)
-zade (1, 2, 3, 4, 5) {'a': 'aa'} -> zade() takes at most 3 non-keyword arguments (5 given)
+zade (1, 2, 3, 4, 5) {'a': 'aa'} -> zade() takes at most 3 non-keyword positional arguments (5 given)
-zade (1, 2, 3, 4, 5) {'d': 'dd'} -> zade() takes at most 3 non-keyword arguments (5 given)
+zade (1, 2, 3, 4, 5) {'d': 'dd'} -> zade() takes at most 3 non-keyword positional arguments (5 given)
-zade (1, 2, 3, 4, 5) {'a': 'aa', 'd': 'dd'} -> zade() takes at most 3 non-keyword arguments (5 given)
+zade (1, 2, 3, 4, 5) {'a': 'aa', 'd': 'dd'} -> zade() takes at most 3 non-keyword positional arguments (5 given)
-zade (1, 2, 3, 4, 5) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> zade() takes at most 3 non-keyword arguments (5 given)
+zade (1, 2, 3, 4, 5) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> zade() takes at most 3 non-keyword positional arguments (5 given)
-zabk () {} -> zabk() takes exactly 2 arguments (0 given)
+zabk () {} -> zabk() takes exactly 2 positional arguments (0 given)
-zabk () {'a': 'aa'} -> zabk() takes exactly 2 non-keyword arguments (1 given)
+zabk () {'a': 'aa'} -> zabk() takes exactly 2 non-keyword positional arguments (1 given)
-zabk () {'d': 'dd'} -> zabk() takes exactly 2 non-keyword arguments (0 given)
+zabk () {'d': 'dd'} -> zabk() takes exactly 2 non-keyword positional arguments (0 given)
-zabk () {'a': 'aa', 'd': 'dd'} -> zabk() takes exactly 2 non-keyword arguments (1 given)
+zabk () {'a': 'aa', 'd': 'dd'} -> zabk() takes exactly 2 non-keyword positional arguments (1 given)
 zabk () {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> ok zabk aa bb D E V {'d': 'dd', 'e': 'ee'}
 zabk (1, 2) {} -> ok zabk 1 2 D E V {}
 zabk (1, 2) {'a': 'aa'} -> zabk() got multiple values for keyword argument 'a'
 zabk (1, 2) {'d': 'dd'} -> ok zabk 1 2 D E V {'d': 'dd'}
 zabk (1, 2) {'a': 'aa', 'd': 'dd'} -> zabk() got multiple values for keyword argument 'a'
 zabk (1, 2) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> zabk() got multiple values for keyword argument 'a'
-zabk (1, 2, 3, 4, 5) {} -> zabk() takes exactly 2 arguments (5 given)
+zabk (1, 2, 3, 4, 5) {} -> zabk() takes exactly 2 positional arguments (5 given)
-zabk (1, 2, 3, 4, 5) {'a': 'aa'} -> zabk() takes exactly 2 non-keyword arguments (5 given)
+zabk (1, 2, 3, 4, 5) {'a': 'aa'} -> zabk() takes exactly 2 non-keyword positional arguments (5 given)
-zabk (1, 2, 3, 4, 5) {'d': 'dd'} -> zabk() takes exactly 2 non-keyword arguments (5 given)
+zabk (1, 2, 3, 4, 5) {'d': 'dd'} -> zabk() takes exactly 2 non-keyword positional arguments (5 given)
-zabk (1, 2, 3, 4, 5) {'a': 'aa', 'd': 'dd'} -> zabk() takes exactly 2 non-keyword arguments (5 given)
+zabk (1, 2, 3, 4, 5) {'a': 'aa', 'd': 'dd'} -> zabk() takes exactly 2 non-keyword positional arguments (5 given)
-zabk (1, 2, 3, 4, 5) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> zabk() takes exactly 2 non-keyword arguments (5 given)
+zabk (1, 2, 3, 4, 5) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> zabk() takes exactly 2 non-keyword positional arguments (5 given)
-zabdv () {} -> zabdv() takes at least 2 arguments (0 given)
+zabdv () {} -> zabdv() takes at least 2 positional arguments (0 given)
-zabdv () {'a': 'aa'} -> zabdv() takes at least 2 non-keyword arguments (1 given)
+zabdv () {'a': 'aa'} -> zabdv() takes at least 2 non-keyword positional arguments (1 given)
-zabdv () {'d': 'dd'} -> zabdv() takes at least 2 non-keyword arguments (0 given)
+zabdv () {'d': 'dd'} -> zabdv() takes at least 2 non-keyword positional arguments (0 given)
-zabdv () {'a': 'aa', 'd': 'dd'} -> zabdv() takes at least 2 non-keyword arguments (1 given)
+zabdv () {'a': 'aa', 'd': 'dd'} -> zabdv() takes at least 2 non-keyword positional arguments (1 given)
 zabdv () {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> zabdv() got an unexpected keyword argument 'e'
 zabdv (1, 2) {} -> ok zabdv 1 2 d E () e
 zabdv (1, 2) {'a': 'aa'} -> zabdv() got multiple values for keyword argument 'a'
@@ -95,10 +95,10 @@ zabdv (1, 2, 3, 4, 5) {'a': 'aa'} -> zabdv() got multiple values for keyword arg
 zabdv (1, 2, 3, 4, 5) {'d': 'dd'} -> zabdv() got multiple values for keyword argument 'd'
 zabdv (1, 2, 3, 4, 5) {'a': 'aa', 'd': 'dd'} -> zabdv() got multiple values for keyword argument 'a'
 zabdv (1, 2, 3, 4, 5) {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> zabdv() got multiple values for keyword argument 'a'
-zabdevk () {} -> zabdevk() takes at least 2 arguments (0 given)
+zabdevk () {} -> zabdevk() takes at least 2 positional arguments (0 given)
-zabdevk () {'a': 'aa'} -> zabdevk() takes at least 2 non-keyword arguments (1 given)
+zabdevk () {'a': 'aa'} -> zabdevk() takes at least 2 non-keyword positional arguments (1 given)
-zabdevk () {'d': 'dd'} -> zabdevk() takes at least 2 non-keyword arguments (0 given)
+zabdevk () {'d': 'dd'} -> zabdevk() takes at least 2 non-keyword positional arguments (0 given)
-zabdevk () {'a': 'aa', 'd': 'dd'} -> zabdevk() takes at least 2 non-keyword arguments (1 given)
+zabdevk () {'a': 'aa', 'd': 'dd'} -> zabdevk() takes at least 2 non-keyword positional arguments (1 given)
 zabdevk () {'a': 'aa', 'b': 'bb', 'd': 'dd', 'e': 'ee'} -> ok zabdevk aa bb dd ee () {}
 zabdevk (1, 2) {} -> ok zabdevk 1 2 d e () {}
 zabdevk (1, 2) {'a': 'aa'} -> zabdevk() got multiple values for keyword argument 'a'

Lib/test/test_ast.py

@@ -151,9 +151,9 @@ def run_tests():
 
 #### EVERYTHING BELOW IS GENERATED #####
 exec_results = [
-('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, None, []), [('Pass', (1, 9))], [])]),
+('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, [], None, [], []), [('Pass', (1, 9))], [])]),
 ('Module', [('ClassDef', (1, 0), 'C', [], [('Pass', (1, 8))])]),
-('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, None, []), [('Return', (1, 8), ('Num', (1, 15), 1))], [])]),
+('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, [], None, [], []), [('Return', (1, 8), ('Num', (1, 15), 1))], [])]),
 ('Module', [('Delete', (1, 0), [('Name', (1, 4), 'v', ('Del',))])]),
 ('Module', [('Assign', (1, 0), [('Name', (1, 0), 'v', ('Store',))], ('Num', (1, 4), 1))]),
 ('Module', [('AugAssign', (1, 0), ('Name', (1, 0), 'v', ('Store',)), ('Add',), ('Num', (1, 5), 1))]),
@@ -180,7 +180,7 @@ eval_results = [
 ('Expression', ('BoolOp', (1, 0), ('And',), [('Name', (1, 0), 'a', ('Load',)), ('Name', (1, 6), 'b', ('Load',))])),
 ('Expression', ('BinOp', (1, 0), ('Name', (1, 0), 'a', ('Load',)), ('Add',), ('Name', (1, 4), 'b', ('Load',)))),
 ('Expression', ('UnaryOp', (1, 0), ('Not',), ('Name', (1, 4), 'v', ('Load',)))),
-('Expression', ('Lambda', (1, 0), ('arguments', [], None, None, []), ('Name', (1, 7), 'None', ('Load',)))),
+('Expression', ('Lambda', (1, 0), ('arguments', [], None, [], None, [], []), ('Name', (1, 7), 'None', ('Load',)))),
 ('Expression', ('Dict', (1, 0), [('Num', (1, 2), 1)], [('Num', (1, 4), 2)])),
 ('Expression', ('ListComp', (1, 1), ('Name', (1, 1), 'a', ('Load',)), [('comprehension', ('Name', (1, 7), 'b', ('Store',)), ('Name', (1, 12), 'c', ('Load',)), [('Name', (1, 17), 'd', ('Load',))])])),
 ('Expression', ('GeneratorExp', (1, 1), ('Name', (1, 1), 'a', ('Load',)), [('comprehension', ('Name', (1, 7), 'b', ('Store',)), ('Name', (1, 12), 'c', ('Load',)), [('Name', (1, 17), 'd', ('Load',))])])),

Lib/test/test_code.py

@@ -9,6 +9,7 @@
 >>> dump(f.func_code)
 name: f
 argcount: 1
+kwonlyargcount: 0
 names: ()
 varnames: ('x', 'g')
 cellvars: ('x',)
@@ -20,6 +21,7 @@ consts: ('None', '<code object g>')
 >>> dump(f(4).func_code)
 name: g
 argcount: 1
+kwonlyargcount: 0
 names: ()
 varnames: ('y',)
 cellvars: ()
@@ -34,9 +36,11 @@ consts: ('None',)
 ...     c = a * b
 ...     return c
 ...
+
 >>> dump(h.func_code)
 name: h
 argcount: 2
+kwonlyargcount: 0
 names: ()
 varnames: ('x', 'y', 'a', 'b', 'c')
 cellvars: ()
@@ -53,6 +57,7 @@ consts: ('None',)
 >>> dump(attrs.func_code)
 name: attrs
 argcount: 1
+kwonlyargcount: 0
 names: ('attr1', 'attr2', 'attr3')
 varnames: ('obj',)
 cellvars: ()
@@ -70,6 +75,7 @@ consts: ('None',)
 >>> dump(optimize_away.func_code)
 name: optimize_away
 argcount: 0
+kwonlyargcount: 0
 names: ()
 varnames: ()
 cellvars: ()
@@ -78,6 +84,22 @@ nlocals: 0
 flags: 67
 consts: ("'doc string'", 'None')
 
+>>> def keywordonly_args(a,b,*,k1):
+...     return a,b,k1
+...
+
+>>> dump(keywordonly_args.func_code)
+name: keywordonly_args
+argcount: 2
+kwonlyargcount: 1
+names: ()
+varnames: ('a', 'b', 'k1')
+cellvars: ()
+freevars: ()
+nlocals: 3
+flags: 67
+consts: ('None',)
+
 """
 
 def consts(t):
@@ -91,8 +113,8 @@ def consts(t):
 
 def dump(co):
     """Print out a text representation of a code object."""
-    for attr in ["name", "argcount", "names", "varnames", "cellvars",
+    for attr in ["name", "argcount", "kwonlyargcount", "names", "varnames",
-                 "freevars", "nlocals", "flags"]:
+                 "cellvars", "freevars", "nlocals", "flags"]:
         print "%s: %s" % (attr, getattr(co, "co_" + attr))
     print "consts:", tuple(consts(co.co_consts))
 

Lib/test/test_compiler.py

@@ -19,36 +19,51 @@ class CompilerTest(unittest.TestCase):
         libdir = os.path.dirname(unittest.__file__)
         testdir = os.path.dirname(test.test_support.__file__)
 
-        for dir in [libdir, testdir]:
+##        for dir in [libdir, testdir]:
-            for basename in os.listdir(dir):
+##            for basename in os.listdir(dir):
-                # Print still working message since this test can be really slow
+##                # Print still working message since this test can be really slow
-                if next_time <= time.time():
+##                if next_time <= time.time():
-                    next_time = time.time() + _PRINT_WORKING_MSG_INTERVAL
+##                    next_time = time.time() + _PRINT_WORKING_MSG_INTERVAL
-                    print >>sys.__stdout__, \
+##                    print >>sys.__stdout__, \
-                       '  testCompileLibrary still working, be patient...'
+##                       '  testCompileLibrary still working, be patient...'
-                    sys.__stdout__.flush()
+##                    sys.__stdout__.flush()
+##
+##                if not basename.endswith(".py"):
+##                    continue
+##                if not TEST_ALL and random() < 0.98:
+##                    continue
+##                path = os.path.join(dir, basename)
+##                if test.test_support.verbose:
+##                    print "compiling", path
+##                f = open(path, "U")
+##                buf = f.read()
+##                f.close()
+##                if "badsyntax" in basename or "bad_coding" in basename:
+##                    self.assertRaises(SyntaxError, compiler.compile,
+##                                      buf, basename, "exec")
+##                else:
+##                    try:
+##                        compiler.compile(buf, basename, "exec")
+##                    except Exception, e:
+##                        args = list(e.args)
+##                        args[0] += "[in file %s]" % basename
+##                        e.args = tuple(args)
+##                        raise
 
-                if not basename.endswith(".py"):
+        path = "/home/jiwon/p3yk/Lib/test/test_keywordonlyarg.py"
-                    continue
-                if not TEST_ALL and random() < 0.98:
-                    continue
-                path = os.path.join(dir, basename)
         if test.test_support.verbose:
             print "compiling", path
         f = open(path, "U")
         buf = f.read()
         f.close()
-                if "badsyntax" in basename or "bad_coding" in basename:
+        #try:
-                    self.assertRaises(SyntaxError, compiler.compile,
+        compiler.compile(buf, "test_keywordonlyarg.py", "exec")
-                                      buf, basename, "exec")
+        #except Exception, e:
-                else:
+        #    args = list(e.args)
-                    try:
+        #    args[0] += "[in file %s]" % path
-                        compiler.compile(buf, basename, "exec")
+        #    e.args = tuple(args)
-                    except Exception, e:
+        #    raise
-                        args = list(e.args)
+
-                        args[0] += "[in file %s]" % basename
-                        e.args = tuple(args)
-                        raise
 
     def testNewClassSyntax(self):
         compiler.compile("class foo():pass\n\n","<string>","exec")

Lib/test/test_frozen.py

@@ -1,4 +1,11 @@
 # Test the frozen module defined in frozen.c.
+# Currently test_frozen fails:
+#   Implementing pep3102(keyword only argument) needs changes in
+#   code object, which needs modification to marshal.
+#   However, to regenerate hard-coded marshal data in frozen.c,
+#   we need to run Tools/freeze/freeze.py, which currently doesn't work
+#   because Lib/modulefinder.py cannot handle relative module import
+#   This test will keep failing until Lib/modulefinder.py is fixed
 
 from test.test_support import TestFailed
 import sys, os

Lib/test/test_grammar.py

@@ -148,7 +148,8 @@ x = eval('1, 0 or 1')
 print 'funcdef'
 ### 'def' NAME parameters ':' suite
 ### parameters: '(' [varargslist] ')'
-### varargslist: (fpdef ['=' test] ',')* ('*' NAME [',' ('**'|'*' '*') NAME]
+### varargslist: (fpdef ['=' test] ',')* 
+###           ('*' (NAME|',' fpdef ['=' test]) [',' ('**'|'*' '*') NAME]
 ###            | ('**'|'*' '*') NAME)
 ###            | fpdef ['=' test] (',' fpdef ['=' test])* [',']
 ### fpdef: NAME | '(' fplist ')'
@@ -265,6 +266,16 @@ def d31v((x)): pass
 d31v(1)
 def d32v((x,)): pass
 d32v((1,))
+#keyword only argument tests
+def pos0key1(*, key): return key
+pos0key1(key=100)
+def pos2key2(p1, p2, *, k1, k2=100): return p1,p2,k1,k2
+pos2key2(1, 2, k1=100)
+pos2key2(1, 2, k1=100, k2=200)
+pos2key2(1, 2, k2=100, k1=200)
+def pos2key2dict(p1, p2, *, k1=100, k2, **kwarg): return p1,p2,k1,k2,kwarg
+pos2key2dict(1,2,k2=100,tokwarg1=100,tokwarg2=200)
+pos2key2dict(1,2,tokwarg1=100,tokwarg2=200, k2=100)
 
 ### lambdef: 'lambda' [varargslist] ':' test
 print 'lambdef'
@@ -279,6 +290,9 @@ l5 = lambda x, y, z=2: x + y + z
 verify(l5(1, 2) == 5)
 verify(l5(1, 2, 3) == 6)
 check_syntax("lambda x: x = 2")
+l6 = lambda x, y, *, k=20: x+y+k
+verify(l6(1,2) == 1+2+20)
+verify(l6(1,2,k=10) == 1+2+10)
 
 ### stmt: simple_stmt | compound_stmt
 # Tested below

Lib/test/test_new.py

@@ -103,6 +103,7 @@ if hasattr(new, 'code'):
 
     c = f.func_code
     argcount = c.co_argcount
+    kwonlyargcount = c.co_kwonlyargcount
     nlocals = c.co_nlocals
     stacksize = c.co_stacksize
     flags = c.co_flags
@@ -117,17 +118,20 @@ if hasattr(new, 'code'):
     freevars = c.co_freevars
     cellvars = c.co_cellvars
 
-    d = new.code(argcount, nlocals, stacksize, flags, codestring,
+    d = new.code(argcount, kwonlyargcount,
+                 nlocals, stacksize, flags, codestring,
                  constants, names, varnames, filename, name,
                  firstlineno, lnotab, freevars, cellvars)
 
     # test backwards-compatibility version with no freevars or cellvars
-    d = new.code(argcount, nlocals, stacksize, flags, codestring,
+    d = new.code(argcount, kwonlyargcount,
+                 nlocals, stacksize, flags, codestring,
                  constants, names, varnames, filename, name,
                  firstlineno, lnotab)
 
     try: # this used to trigger a SystemError
-        d = new.code(-argcount, nlocals, stacksize, flags, codestring,
+        d = new.code(-argcount, kwonlyargcount,
+                     nlocals, stacksize, flags, codestring,
                      constants, names, varnames, filename, name,
                      firstlineno, lnotab)
     except ValueError:
@@ -136,7 +140,8 @@ if hasattr(new, 'code'):
         raise TestFailed, "negative co_argcount didn't trigger an exception"
 
     try: # this used to trigger a SystemError
-        d = new.code(argcount, -nlocals, stacksize, flags, codestring,
+        d = new.code(argcount, kwonlyargcount,
+                     -nlocals, stacksize, flags, codestring,
                      constants, names, varnames, filename, name,
                      firstlineno, lnotab)
     except ValueError:
@@ -145,7 +150,8 @@ if hasattr(new, 'code'):
         raise TestFailed, "negative co_nlocals didn't trigger an exception"
 
     try: # this used to trigger a Py_FatalError!
-        d = new.code(argcount, nlocals, stacksize, flags, codestring,
+        d = new.code(argcount, kwonlyargcount,
+                     nlocals, stacksize, flags, codestring,
                      constants, (5,), varnames, filename, name,
                      firstlineno, lnotab)
     except TypeError:
@@ -156,7 +162,8 @@ if hasattr(new, 'code'):
     # new.code used to be a way to mutate a tuple...
     class S(str): pass
     t = (S("ab"),)
-    d = new.code(argcount, nlocals, stacksize, flags, codestring,
+    d = new.code(argcount, kwonlyargcount,
+                 nlocals, stacksize, flags, codestring,
                  constants, t, varnames, filename, name,
                  firstlineno, lnotab)
     verify(type(t[0]) is S, "eek, tuple changed under us!")

Modules/_ctypes/callbacks.c

@@ -51,6 +51,7 @@ void _AddTraceback(char *funcname, char *filename, int lineno)
 	if (!empty_string) goto bad;
 	py_code = PyCode_New(
 		0,            /*int argcount,*/
+		0,            /*int kwonlyargcount,*/
 		0,            /*int nlocals,*/
 		0,            /*int stacksize,*/
 		0,            /*int flags,*/

Modules/parsermodule.c

@@ -1105,13 +1105,13 @@ validate_testlist_safe(node *tree)
 }
 
 
-/* '*' NAME [',' '**' NAME] | '**' NAME
+/* '*' [NAME] (',' NAME ['=' test])* [',' '**' NAME] | '**' NAME
  */
 static int
 validate_varargslist_trailer(node *tree, int start)
 {
     int nch = NCH(tree);
-    int res = 0;
+    int res = 0, i;
     int sym;
 
     if (nch <= start) {
@@ -1121,15 +1121,40 @@ validate_varargslist_trailer(node *tree, int start)
     sym = TYPE(CHILD(tree, start));
     if (sym == STAR) {
         /*
-         *  ('*' NAME [',' '**' NAME]
+         * '*' [NAME] (',' NAME ['=' test])* [',' '**' NAME] | '**' NAME
          */
         if (nch-start == 2)
             res = validate_name(CHILD(tree, start+1), NULL);
-        else if (nch-start == 5)
+        else if (nch-start == 5 && TYPE(CHILD(tree, start+2)) == COMMA)
             res = (validate_name(CHILD(tree, start+1), NULL)
                    && validate_comma(CHILD(tree, start+2))
                    && validate_doublestar(CHILD(tree, start+3))
                    && validate_name(CHILD(tree, start+4), NULL));
+        else {
+            /* skip over [NAME] (',' NAME ['=' test])*  */
+            i = start + 1;
+	    if (TYPE(CHILD(tree, i)) == NAME) { /* skip over [NAME] */
+		i += 1;
+	    }
+            while (res && i+1 < nch) { /* validate  (',' NAME ['=' test])* */
+                res = validate_comma(CHILD(tree, i));
+                if (TYPE(CHILD(tree, i+1)) == DOUBLESTAR) 
+                    break;
+                res = res && validate_name(CHILD(tree, i+1), NULL);
+                if (res && i+2 < nch && TYPE(CHILD(tree, i+2)) == EQUAL) {
+                    res = res && (i+3 < nch) 
+                          && validate_test(CHILD(tree, i+3));
+                    i += 4;
+                }
+                else {
+                    i += 2;
+                }
+            }
+            /* [',' '**' NAME] */
+            if (res && i+1 < nch && TYPE(CHILD(tree, i+1)) == DOUBLESTAR) {
+                res = validate_name(CHILD(tree, i+2), NULL);
+            }
+        }
     }
     else if (sym == DOUBLESTAR) {
         /*
@@ -1148,8 +1173,7 @@ validate_varargslist_trailer(node *tree, int start)
  *
  *  varargslist:
  *      (fpdef ['=' test] ',')*
- *           ('*' NAME [',' '**' NAME]
+ *      ('*' [NAME] (',' NAME ['=' test])* [',' '**' NAME] | '**' NAME)
- *         | '**' NAME)
  *      | fpdef ['=' test] (',' fpdef ['=' test])* [',']
  *
  */
@@ -1169,7 +1193,7 @@ validate_varargslist(node *tree)
     sym = TYPE(CHILD(tree, 0));
     if (sym == STAR || sym == DOUBLESTAR)
         /* whole thing matches:
-         *      '*' NAME [',' '**' NAME] | '**' NAME
+         *    '*' [NAME] (',' NAME ['=' test])* [',' '**' NAME] | '**' NAME
          */
         res = validate_varargslist_trailer(tree, 0);
     else if (sym == fpdef) {
@@ -1201,7 +1225,7 @@ validate_varargslist(node *tree)
                         break;
                 }
             }
-            /* ... '*' NAME [',' '**' NAME] | '**' NAME
+            /* .. ('*' [NAME] (',' NAME ['=' test])* [',' '**' NAME] | '**' NAME)
              * i --^^^
              */
             if (res)

Modules/pyexpat.c

@@ -279,6 +279,7 @@ getcode(enum HandlerTypes slot, char* func_name, int lineno)
         filename = PyString_FromString(__FILE__);
         handler_info[slot].tb_code =
             PyCode_New(0,		/* argcount */
+                       0,       /* kwonlyargcount */
                        0,		/* nlocals */
                        0,		/* stacksize */
                        0,		/* flags */

Objects/codeobject.c

@@ -41,7 +41,8 @@ intern_strings(PyObject *tuple)
 
 
 PyCodeObject *
-PyCode_New(int argcount, int nlocals, int stacksize, int flags,
+PyCode_New(int argcount, int kwonlyargcount,
+	   int nlocals, int stacksize, int flags,
 	   PyObject *code, PyObject *consts, PyObject *names,
 	   PyObject *varnames, PyObject *freevars, PyObject *cellvars,
 	   PyObject *filename, PyObject *name, int firstlineno,
@@ -80,6 +81,7 @@ PyCode_New(int argcount, int nlocals, int stacksize, int flags,
 	co = PyObject_NEW(PyCodeObject, &PyCode_Type);
 	if (co != NULL) {
 		co->co_argcount = argcount;
+		co->co_kwonlyargcount = kwonlyargcount;
 		co->co_nlocals = nlocals;
 		co->co_stacksize = stacksize;
 		co->co_flags = flags;
@@ -112,6 +114,7 @@ PyCode_New(int argcount, int nlocals, int stacksize, int flags,
 
 static PyMemberDef code_memberlist[] = {
 	{"co_argcount",	T_INT,		OFF(co_argcount),	READONLY},
+	{"co_kwonlyargcount",	T_INT,	OFF(co_kwonlyargcount),	READONLY},
 	{"co_nlocals",	T_INT,		OFF(co_nlocals),	READONLY},
 	{"co_stacksize",T_INT,		OFF(co_stacksize),	READONLY},
 	{"co_flags",	T_INT,		OFF(co_flags),		READONLY},
@@ -182,6 +185,7 @@ static PyObject *
 code_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 {
 	int argcount;
+	int kwonlyargcount;
 	int nlocals;
 	int stacksize;
 	int flags;
@@ -197,8 +201,9 @@ code_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 	int firstlineno;
 	PyObject *lnotab;
 
-	if (!PyArg_ParseTuple(args, "iiiiSO!O!O!SSiS|O!O!:code",
+	if (!PyArg_ParseTuple(args, "iiiiiSO!O!O!SSiS|O!O!:code",
-			      &argcount, &nlocals, &stacksize, &flags,
+			      &argcount, &kwonlyargcount,
+				  &nlocals, &stacksize, &flags,
 			      &code,
 			      &PyTuple_Type, &consts,
 			      &PyTuple_Type, &names,
@@ -216,6 +221,12 @@ code_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 		goto cleanup;
 	}
 
+	if (kwonlyargcount < 0) {
+		PyErr_SetString(
+			PyExc_ValueError,
+			"code: kwonlyargcount must not be negative");
+		goto cleanup;
+	}
 	if (nlocals < 0) {
 		PyErr_SetString(
 			PyExc_ValueError,
@@ -242,7 +253,8 @@ code_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 	if (ourcellvars == NULL)
 		goto cleanup;
 
-	co = (PyObject *)PyCode_New(argcount, nlocals, stacksize, flags,
+	co = (PyObject *)PyCode_New(argcount, kwonlyargcount,
+				    nlocals, stacksize, flags,
 				    code, consts, ournames, ourvarnames,
 				    ourfreevars, ourcellvars, filename,
 				    name, firstlineno, lnotab);
@@ -312,6 +324,8 @@ code_richcompare(PyObject *self, PyObject *other, int op)
 	if (eq <= 0) goto unequal;
 	eq = co->co_argcount == cp->co_argcount;
 	if (!eq) goto unequal;
+	eq = co->co_kwonlyargcount == cp->co_kwonlyargcount;
+	if (!eq) goto unequal;
 	eq = co->co_nlocals == cp->co_nlocals;
 	if (!eq) goto unequal;
 	eq = co->co_flags == cp->co_flags;
@@ -369,7 +383,8 @@ code_hash(PyCodeObject *co)
 	h6 = PyObject_Hash(co->co_cellvars);
 	if (h6 == -1) return -1;
 	h = h0 ^ h1 ^ h2 ^ h3 ^ h4 ^ h5 ^ h6 ^
-		co->co_argcount ^ co->co_nlocals ^ co->co_flags;
+		co->co_argcount ^ co->co_kwonlyargcount ^
+		co->co_nlocals ^ co->co_flags;
 	if (h == -1) h = -2;
 	return h;
 }

Objects/funcobject.c

@@ -24,6 +24,7 @@ PyFunction_New(PyObject *code, PyObject *globals)
 		op->func_name = ((PyCodeObject *)code)->co_name;
 		Py_INCREF(op->func_name);
 		op->func_defaults = NULL; /* No default arguments */
+		op->func_kwdefaults = NULL; /* No keyword only defaults */
 		op->func_closure = NULL;
 		consts = ((PyCodeObject *)code)->co_consts;
 		if (PyTuple_Size(consts) >= 1) {
@@ -121,6 +122,38 @@ PyFunction_SetDefaults(PyObject *op, PyObject *defaults)
 	return 0;
 }
 
+PyObject *
+PyFunction_GetKwDefaults(PyObject *op)
+{
+	if (!PyFunction_Check(op)) {
+		PyErr_BadInternalCall();
+		return NULL;
+	}
+	return ((PyFunctionObject *) op) -> func_kwdefaults;
+}
+
+int
+PyFunction_SetKwDefaults(PyObject *op, PyObject *defaults)
+{
+	if (!PyFunction_Check(op)) {
+		PyErr_BadInternalCall();
+		return -1;
+	}
+	if (defaults == Py_None)
+		defaults = NULL;
+	else if (defaults && PyDict_Check(defaults)) {
+		Py_INCREF(defaults);
+	}
+	else {
+		PyErr_SetString(PyExc_SystemError,
+				"non-dict keyword only default args");
+		return -1;
+	}
+	Py_XDECREF(((PyFunctionObject *)op) -> func_kwdefaults);
+	((PyFunctionObject *) op) -> func_kwdefaults = defaults;
+	return 0;
+}
+
 PyObject *
 PyFunction_GetClosure(PyObject *op)
 {
@@ -325,10 +358,49 @@ func_set_defaults(PyFunctionObject *op, PyObject *value)
 	return 0;
 }
 
+static PyObject *
+func_get_kwdefaults(PyFunctionObject *op)
+{
+	if (restricted())
+		return NULL;
+	if (op->func_kwdefaults == NULL) {
+		Py_INCREF(Py_None);
+		return Py_None;
+	}
+	Py_INCREF(op->func_kwdefaults);
+	return op->func_kwdefaults;
+}
+
+static int
+func_set_kwdefaults(PyFunctionObject *op, PyObject *value)
+{
+	PyObject *tmp;
+    
+	if (restricted())
+		return -1;
+
+	if (value == Py_None)
+		value = NULL;
+	/* Legal to del f.func_defaults.
+	 * Can only set func_kwdefaults to NULL or a dict. */
+	if (value != NULL && !PyDict_Check(value)) {
+		PyErr_SetString(PyExc_TypeError,
+			"func_kwdefaults must be set to a dict object");
+		return -1;
+	}
+	tmp = op->func_kwdefaults;
+	Py_XINCREF(value);
+	op->func_kwdefaults = value;
+	Py_XDECREF(tmp);
+	return 0;
+}
+
 static PyGetSetDef func_getsetlist[] = {
         {"func_code", (getter)func_get_code, (setter)func_set_code},
         {"func_defaults", (getter)func_get_defaults,
 	 (setter)func_set_defaults},
+	{"func_kwdefaults", (getter)func_get_kwdefaults,
+	 (setter)func_set_kwdefaults},
 	{"func_dict", (getter)func_get_dict, (setter)func_set_dict},
 	{"__dict__", (getter)func_get_dict, (setter)func_set_dict},
 	{"func_name", (getter)func_get_name, (setter)func_set_name},
@@ -519,6 +591,7 @@ function_call(PyObject *func, PyObject *arg, PyObject *kw)
 		PyFunction_GET_GLOBALS(func), (PyObject *)NULL,
 		&PyTuple_GET_ITEM(arg, 0), PyTuple_Size(arg),
 		k, nk, d, nd,
+		PyFunction_GET_KW_DEFAULTS(func),
 		PyFunction_GET_CLOSURE(func));
 
 	if (k != NULL)

Parser/Python.asdl

@@ -100,8 +100,8 @@ module Python version "$Revision$"
 	excepthandler = (expr? type, expr? name, stmt* body, int lineno,
 	                 int col_offset)
 
-	arguments = (expr* args, identifier? vararg, 
+	arguments = (expr* args, identifier? vararg, expr* kwonlyargs,
-		     identifier? kwarg, expr* defaults)
+		         identifier? kwarg, expr* defaults, expr* kw_defaults)
 
         -- keyword arguments supplied to call
         keyword = (identifier arg, expr value)

Python/Python-ast.c

@@ -333,8 +333,10 @@ static PyObject* ast2obj_arguments(void*);
 static char *arguments_fields[]={
         "args",
         "vararg",
+        "kwonlyargs",
         "kwarg",
         "defaults",
+        "kw_defaults",
 };
 static PyTypeObject *keyword_type;
 static PyObject* ast2obj_keyword(void*);
@@ -708,7 +710,7 @@ static int init_types(void)
         excepthandler_type = make_type("excepthandler", AST_type,
                                        excepthandler_fields, 5);
         if (!excepthandler_type) return 0;
-        arguments_type = make_type("arguments", AST_type, arguments_fields, 4);
+        arguments_type = make_type("arguments", AST_type, arguments_fields, 6);
         if (!arguments_type) return 0;
         keyword_type = make_type("keyword", AST_type, keyword_fields, 2);
         if (!keyword_type) return 0;
@@ -1828,8 +1830,8 @@ excepthandler(expr_ty type, expr_ty name, asdl_seq * body, int lineno, int
 }
 
 arguments_ty
-arguments(asdl_seq * args, identifier vararg, identifier kwarg, asdl_seq *
+arguments(asdl_seq * args, identifier vararg, asdl_seq * kwonlyargs, identifier
-          defaults, PyArena *arena)
+          kwarg, asdl_seq * defaults, asdl_seq * kw_defaults, PyArena *arena)
 {
         arguments_ty p;
         p = (arguments_ty)PyArena_Malloc(arena, sizeof(*p));
@@ -1839,8 +1841,10 @@ arguments(asdl_seq * args, identifier vararg, identifier kwarg, asdl_seq *
         }
         p->args = args;
         p->vararg = vararg;
+        p->kwonlyargs = kwonlyargs;
         p->kwarg = kwarg;
         p->defaults = defaults;
+        p->kw_defaults = kw_defaults;
         return p;
 }
 
@@ -2907,6 +2911,11 @@ ast2obj_arguments(void* _o)
         if (PyObject_SetAttrString(result, "vararg", value) == -1)
                 goto failed;
         Py_DECREF(value);
+        value = ast2obj_list(o->kwonlyargs, ast2obj_expr);
+        if (!value) goto failed;
+        if (PyObject_SetAttrString(result, "kwonlyargs", value) == -1)
+                goto failed;
+        Py_DECREF(value);
         value = ast2obj_identifier(o->kwarg);
         if (!value) goto failed;
         if (PyObject_SetAttrString(result, "kwarg", value) == -1)
@@ -2917,6 +2926,11 @@ ast2obj_arguments(void* _o)
         if (PyObject_SetAttrString(result, "defaults", value) == -1)
                 goto failed;
         Py_DECREF(value);
+        value = ast2obj_list(o->kw_defaults, ast2obj_expr);
+        if (!value) goto failed;
+        if (PyObject_SetAttrString(result, "kw_defaults", value) == -1)
+                goto failed;
+        Py_DECREF(value);
         return result;
 failed:
         Py_XDECREF(value);
@@ -2994,7 +3008,7 @@ init_ast(void)
         if (PyDict_SetItemString(d, "AST", (PyObject*)AST_type) < 0) return;
         if (PyModule_AddIntConstant(m, "PyCF_ONLY_AST", PyCF_ONLY_AST) < 0)
                 return;
-        if (PyModule_AddStringConstant(m, "__version__", "51631") < 0)
+        if (PyModule_AddStringConstant(m, "__version__", "51773") < 0)
                 return;
         if (PyDict_SetItemString(d, "mod", (PyObject*)mod_type) < 0) return;
         if (PyDict_SetItemString(d, "Module", (PyObject*)Module_type) < 0)

Python/ast.c

@@ -591,6 +591,63 @@ compiler_complex_args(struct compiling *c, const node *n)
     return result;
 }
 
+/* returns -1 if failed to handle keyword only arguments
+   returns new position to keep processing if successful
+               (',' NAME ['=' test])* 
+                     ^^^
+   start pointing here
+ */
+static int
+handle_keywordonly_args(struct compiling *c, const node *n, int start,
+                        asdl_seq *kwonlyargs, asdl_seq *kwdefaults)
+{
+    node *ch;
+    expr_ty name;
+    int i = start;
+    int j = 0; /* index for kwdefaults and kwonlyargs */
+    assert(kwonlyargs != NULL);
+    assert(kwdefaults != NULL);
+    while (i < NCH(n)) {
+        ch = CHILD(n, i);
+        switch (TYPE(ch)) {
+            case NAME:
+                if (i + 1 < NCH(n) && TYPE(CHILD(n, i + 1)) == EQUAL) {
+                    expr_ty expression = ast_for_expr(c, CHILD(n, i + 2));
+                    if (!expression) {
+                        ast_error(ch, "assignment to None");
+                        goto error;
+                    }
+                    asdl_seq_SET(kwdefaults, j, expression);
+                    i += 2; /* '=' and test */
+                }
+                else { /* setting NULL if no default value exists */
+                    asdl_seq_SET(kwdefaults, j, NULL);
+                }
+                if (!strcmp(STR(ch), "None")) {
+                    ast_error(ch, "assignment to None");
+                    goto error;
+                }
+                name = Name(NEW_IDENTIFIER(ch),
+                            Param, LINENO(ch), ch->n_col_offset,
+                            c->c_arena);
+                if (!name) {
+                    ast_error(ch, "expecting name");
+                    goto error;
+                }
+                asdl_seq_SET(kwonlyargs, j++, name);
+                i += 2; /* the name and the comma */
+                break;
+            case DOUBLESTAR:
+                return i;
+            default:
+                ast_error(ch, "unexpected node");
+                goto error;
+        }
+    }
+    return i;
+ error:
+    return -1;   
+}
 
 /* Create AST for argument list. */
 
@@ -598,35 +655,71 @@ static arguments_ty
 ast_for_arguments(struct compiling *c, const node *n)
 {
     /* parameters: '(' [varargslist] ')'
-       varargslist: (fpdef ['=' test] ',')* ('*' NAME [',' '**' NAME]
+       varargslist: (fpdef ['=' test] ',')* 
-            | '**' NAME) | fpdef ['=' test] (',' fpdef ['=' test])* [',']
+             ('*' [NAME] (',' fpdef ['=' test])* [',' '**' NAME] | '**' NAME)
+             | fpdef ['=' test] (',' fpdef ['=' test])* [',']
     */
-    int i, j, k, n_args = 0, n_defaults = 0, found_default = 0;
+    int i, j, k, nposargs = 0, nkwonlyargs = 0;
-    asdl_seq *args, *defaults;
+    int nposdefaults = 0, found_default = 0;
+    asdl_seq *posargs, *posdefaults, *kwonlyargs, *kwdefaults;
     identifier vararg = NULL, kwarg = NULL;
     node *ch;
 
     if (TYPE(n) == parameters) {
         if (NCH(n) == 2) /* () as argument list */
-	    return arguments(NULL, NULL, NULL, NULL, c->c_arena);
+            return arguments(NULL, NULL, NULL, NULL, NULL, NULL, c->c_arena);
         n = CHILD(n, 1);
     }
     REQ(n, varargslist);
 
-    /* first count the number of normal args & defaults */
+    /* first count the number of positional args & defaults */
     for (i = 0; i < NCH(n); i++) {
         ch = CHILD(n, i);
-	if (TYPE(ch) == fpdef)
+        if (TYPE(ch) == STAR) {
-	    n_args++;
+            if (TYPE(CHILD(n, i+1)) == NAME) {
-	if (TYPE(ch) == EQUAL)
+            /* skip NAME of vararg */
-	    n_defaults++;
+            /* so that following can count only keyword only args */
+                i += 2;
             }
-    args = (n_args ? asdl_seq_new(n_args, c->c_arena) : NULL);
+            else {
-    if (!args && n_args)
+                i++;
+            }
+            break; 
+        }
+        if (TYPE(ch) == fpdef) nposargs++;
+        if (TYPE(ch) == EQUAL) nposdefaults++;
+    }
+    /* count the number of keyword only args & 
+       defaults for keyword only args */
+    for ( ; i < NCH(n); ++i) {
+        ch = CHILD(n, i);
+        if (TYPE(ch) == DOUBLESTAR) break;
+        if (TYPE(ch) == NAME) nkwonlyargs++;
+    }
+
+    posargs = (nposargs ? asdl_seq_new(nposargs, c->c_arena) : NULL);
+    if (!posargs && nposargs)
             return NULL; /* Don't need to goto error; no objects allocated */
-    defaults = (n_defaults ? asdl_seq_new(n_defaults, c->c_arena) : NULL);
+    kwonlyargs = (nkwonlyargs ?
-    if (!defaults && n_defaults)
+                   asdl_seq_new(nkwonlyargs, c->c_arena) : NULL);
+    if (!kwonlyargs && nkwonlyargs)
             return NULL; /* Don't need to goto error; no objects allocated */
+    posdefaults = (nposdefaults ? 
+                    asdl_seq_new(nposdefaults, c->c_arena) : NULL);
+    if (!posdefaults && nposdefaults)
+            return NULL; /* Don't need to goto error; no objects allocated */
+    /* The length of kwonlyargs and kwdefaults are same 
+       since we set NULL as default for keyword only argument w/o default
+       - we have sequence data structure, but no dictionary */
+    kwdefaults = (nkwonlyargs ? 
+                   asdl_seq_new(nkwonlyargs, c->c_arena) : NULL);
+    if (!kwdefaults && nkwonlyargs)
+            return NULL; /* Don't need to goto error; no objects allocated */
+
+    if (nposargs + nkwonlyargs > 255) {
+		ast_error(n, "more than 255 arguments");
+		return NULL;
+    }
 
     /* fpdef: NAME | '(' fplist ')'
        fplist: fpdef (',' fpdef)* [',']
@@ -645,8 +738,9 @@ ast_for_arguments(struct compiling *c, const node *n)
                     expr_ty expression = ast_for_expr(c, CHILD(n, i + 2));
                     if (!expression)
                         goto error;
-                    assert(defaults != NULL);
+                    assert(posdefaults != NULL);
-                    asdl_seq_SET(defaults, j++, expression);
+                    asdl_seq_SET(posdefaults, j++, expression);
+
                     i += 2;
                     found_default = 1;
                 }
@@ -660,7 +754,8 @@ ast_for_arguments(struct compiling *c, const node *n)
                     /* def foo((x)): is not complex, special case. */
                     if (NCH(ch) != 1) {
                         /* We have complex arguments, setup for unpacking. */
-			asdl_seq_SET(args, k++, compiler_complex_args(c, ch));
+                        asdl_seq_SET(posargs, k++,
+                                     compiler_complex_args(c, ch));
                     } else {
                         /* def foo((x)): setup for checking NAME below. */
                         ch = CHILD(ch, 0);
@@ -677,18 +772,39 @@ ast_for_arguments(struct compiling *c, const node *n)
                                 c->c_arena);
                     if (!name)
                         goto error;
-                    asdl_seq_SET(args, k++, name);
+                    asdl_seq_SET(posargs, k++, name);
                                          
                 }
                 i += 2; /* the name and the comma */
                 break;
             case STAR:
+                if (i+1 >= NCH(n)) {
+                    ast_error(CHILD(n, i), "no name for vararg");
+		    goto error;
+                }
                 if (!strcmp(STR(CHILD(n, i+1)), "None")) {
                         ast_error(CHILD(n, i+1), "assignment to None");
                         goto error;
                 }
+                if (TYPE(CHILD(n, i+1)) == COMMA) {
+                    int res = 0;    
+                    i += 2; /* now follows keyword only arguments */
+                    res = handle_keywordonly_args(c, n, i,
+                                                  kwonlyargs, kwdefaults);
+                    if (res == -1) goto error;
+                    i = res; /* res has new position to process */
+                }
+                else {
                     vararg = NEW_IDENTIFIER(CHILD(n, i+1));
                     i += 3;
+                    if (i < NCH(n) && TYPE(CHILD(n, i)) == NAME) {
+                        int res = 0;
+                        res = handle_keywordonly_args(c, n, i,
+                                                      kwonlyargs, kwdefaults);
+                        if (res == -1) goto error;
+                        i = res; /* res has new position to process */
+                    }
+                }
                 break;
             case DOUBLESTAR:
                 if (!strcmp(STR(CHILD(n, i+1)), "None")) {
@@ -705,9 +821,8 @@ ast_for_arguments(struct compiling *c, const node *n)
                 goto error;
         }
     }
-
+    return arguments(posargs, vararg, kwonlyargs, kwarg, 
-    return arguments(args, vararg, kwarg, defaults, c->c_arena);
+                     posdefaults, kwdefaults, c->c_arena);
-
  error:
     Py_XDECREF(vararg);
     Py_XDECREF(kwarg);
@@ -851,7 +966,7 @@ ast_for_lambdef(struct compiling *c, const node *n)
     expr_ty expression;
 
     if (NCH(n) == 3) {
-        args = arguments(NULL, NULL, NULL, NULL, c->c_arena);
+        args = arguments(NULL, NULL, NULL, NULL, NULL, NULL, c->c_arena);
         if (!args)
             return NULL;
         expression = ast_for_expr(c, CHILD(n, 2));

Python/ceval.c

@@ -494,7 +494,7 @@ PyEval_EvalCode(PyCodeObject *co, PyObject *globals, PyObject *locals)
 			  (PyObject **)NULL, 0,
 			  (PyObject **)NULL, 0,
 			  (PyObject **)NULL, 0,
-			  NULL);
+			  NULL, NULL);
 }
 
 
@@ -2290,26 +2290,46 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
 		}
 
 		case MAKE_FUNCTION:
+		{
+		    int posdefaults = oparg & 0xff;
+		    int kwdefaults = (oparg>>8) & 0xff;
+
 			v = POP(); /* code object */
 			x = PyFunction_New(v, f->f_globals);
 			Py_DECREF(v);
 			/* XXX Maybe this should be a separate opcode? */
-			if (x != NULL && oparg > 0) {
+			if (x != NULL && posdefaults > 0) {
-				v = PyTuple_New(oparg);
+				v = PyTuple_New(posdefaults);
 				if (v == NULL) {
 					Py_DECREF(x);
 					x = NULL;
 					break;
 				}
-				while (--oparg >= 0) {
+				while (--posdefaults >= 0) {
 					w = POP();
-					PyTuple_SET_ITEM(v, oparg, w);
+					PyTuple_SET_ITEM(v, posdefaults, w);
 				}
 				err = PyFunction_SetDefaults(x, v);
 				Py_DECREF(v);
 			}
+			if (x != NULL && kwdefaults > 0) {
+				v = PyDict_New();
+				if (v == NULL) {
+					Py_DECREF(x);
+					x = NULL;
+					break;
+				}
+				while (--kwdefaults >= 0) {
+					w = POP(); /* default value */
+					u = POP(); /* kw only arg name */
+					PyDict_SetItem(v, u, w);
+				}
+				err = PyFunction_SetKwDefaults(x, v);
+				Py_DECREF(v);
+			}
 			PUSH(x);
 			break;
+		}
 
 		case MAKE_CLOSURE:
 		{
@@ -2577,7 +2597,7 @@ fast_yield:
 PyObject *
 PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals,
 	   PyObject **args, int argcount, PyObject **kws, int kwcount,
-	   PyObject **defs, int defcount, PyObject *closure)
+	   PyObject **defs, int defcount, PyObject *kwdefs, PyObject *closure)
 {
 	register PyFrameObject *f;
 	register PyObject *retval = NULL;
@@ -2601,6 +2621,7 @@ PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals,
 	freevars = f->f_localsplus + co->co_nlocals;
 
 	if (co->co_argcount > 0 ||
+	    co->co_kwonlyargcount > 0 ||
 	    co->co_flags & (CO_VARARGS | CO_VARKEYWORDS)) {
 		int i;
 		int n = argcount;
@@ -2609,7 +2630,7 @@ PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals,
 			kwdict = PyDict_New();
 			if (kwdict == NULL)
 				goto fail;
-			i = co->co_argcount;
+			i = co->co_argcount + co->co_kwonlyargcount;
 			if (co->co_flags & CO_VARARGS)
 				i++;
 			SETLOCAL(i, kwdict);
@@ -2618,7 +2639,7 @@ PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals,
 			if (!(co->co_flags & CO_VARARGS)) {
 				PyErr_Format(PyExc_TypeError,
 				    "%.200s() takes %s %d "
-				    "%sargument%s (%d given)",
+				    "%spositional argument%s (%d given)",
 				    PyString_AsString(co->co_name),
 				    defcount ? "at most" : "exactly",
 				    co->co_argcount,
@@ -2638,7 +2659,7 @@ PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals,
 			u = PyTuple_New(argcount - n);
 			if (u == NULL)
 				goto fail;
-			SETLOCAL(co->co_argcount, u);
+			SETLOCAL(co->co_argcount + co->co_kwonlyargcount, u);
 			for (i = n; i < argcount; i++) {
 				x = args[i];
 				Py_INCREF(x);
@@ -2656,7 +2677,9 @@ PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals,
 				goto fail;
 			}
 			/* XXX slow -- speed up using dictionary? */
-			for (j = 0; j < co->co_argcount; j++) {
+			for (j = 0;
+			     j < co->co_argcount + co->co_kwonlyargcount;
+			     j++) {
 				PyObject *nm = PyTuple_GET_ITEM(
 					co->co_varnames, j);
 				int cmp = PyObject_RichCompareBool(
@@ -2669,7 +2692,7 @@ PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals,
 			/* Check errors from Compare */
 			if (PyErr_Occurred())
 				goto fail;
-			if (j >= co->co_argcount) {
+			if (j >= co->co_argcount + co->co_kwonlyargcount) {
 				if (kwdict == NULL) {
 					PyErr_Format(PyExc_TypeError,
 					    "%.200s() got an unexpected "
@@ -2694,13 +2717,38 @@ PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals,
 				SETLOCAL(j, value);
 			}
 		}
+		if (co->co_kwonlyargcount > 0) {
+			for (i = co->co_argcount;
+			     i < co->co_argcount + co->co_kwonlyargcount;
+			     i++) {
+				if (GETLOCAL(i) != NULL)
+					continue;
+				PyObject *name =
+				    PyTuple_GET_ITEM(co->co_varnames, i);
+				PyObject *def = NULL;
+				if (kwdefs != NULL)
+					def = PyDict_GetItem(kwdefs, name);
+				if (def != NULL) {
+					Py_INCREF(def);
+					SETLOCAL(i, def);
+					continue;
+				}
+				PyErr_Format(PyExc_TypeError,
+					"%.200s() needs "
+					"keyword only argument %s",
+					PyString_AsString(co->co_name),
+					PyString_AsString(name));
+				goto fail;
+			}
+		}
 		if (argcount < co->co_argcount) {
 			int m = co->co_argcount - defcount;
 			for (i = argcount; i < m; i++) {
 				if (GETLOCAL(i) == NULL) {
 					PyErr_Format(PyExc_TypeError,
 					    "%.200s() takes %s %d "
-					    "%sargument%s (%d given)",
+					    "%spositional argument%s "
+					    "(%d given)",
 					    PyString_AsString(co->co_name),
 					    ((co->co_flags & CO_VARARGS) ||
 					     defcount) ? "at least"
@@ -3565,12 +3613,14 @@ fast_function(PyObject *func, PyObject ***pp_stack, int n, int na, int nk)
 	PyCodeObject *co = (PyCodeObject *)PyFunction_GET_CODE(func);
 	PyObject *globals = PyFunction_GET_GLOBALS(func);
 	PyObject *argdefs = PyFunction_GET_DEFAULTS(func);
+	PyObject *kwdefs = PyFunction_GET_KW_DEFAULTS(func);
 	PyObject **d = NULL;
 	int nd = 0;
 
 	PCALL(PCALL_FUNCTION);
 	PCALL(PCALL_FAST_FUNCTION);
-	if (argdefs == NULL && co->co_argcount == n && nk==0 &&
+	if (argdefs == NULL && co->co_argcount == n &&
+	    co->co_kwonlyargcount == 0 && nk==0 &&
 	    co->co_flags == (CO_OPTIMIZED | CO_NEWLOCALS | CO_NOFREE)) {
 		PyFrameObject *f;
 		PyObject *retval = NULL;
@@ -3608,7 +3658,7 @@ fast_function(PyObject *func, PyObject ***pp_stack, int n, int na, int nk)
 	}
 	return PyEval_EvalCodeEx(co, globals,
 				 (PyObject *)NULL, (*pp_stack)-n, na,
-				 (*pp_stack)-2*nk, nk, d, nd,
+				 (*pp_stack)-2*nk, nk, d, nd, kwdefs,
 				 PyFunction_GET_CLOSURE(func));
 }
 

Python/compile.c

@@ -115,6 +115,7 @@ struct compiler_unit {
 	PyObject *u_private;	/* for private name mangling */
 
 	int u_argcount;	   /* number of arguments for block */ 
+	int u_kwonlyargcount; /* number of keyword only arguments for block */
     /* Pointer to the most recently allocated block.  By following b_list
        members, you can reach all early allocated blocks. */
 	basicblock *u_blocks;
@@ -494,6 +495,7 @@ compiler_enter_scope(struct compiler *c, identifier name, void *key,
 	}
 	memset(u, 0, sizeof(struct compiler_unit));
 	u->u_argcount = 0;
+	u->u_kwonlyargcount = 0;
 	u->u_ste = PySymtable_Lookup(c->c_st, key);
 	if (!u->u_ste) {
 		compiler_unit_free(u);
@@ -896,9 +898,9 @@ opcode_stack_effect(int opcode, int oparg)
 			return -NARGS(oparg)-1;
 		case CALL_FUNCTION_VAR_KW:
 			return -NARGS(oparg)-2;
-#undef NARGS
 		case MAKE_FUNCTION:
-			return -oparg;
+			return -NARGS(oparg);
+#undef NARGS
 		case BUILD_SLICE:
 			if (oparg == 3)
 				return -2;
@@ -1346,6 +1348,25 @@ compiler_arguments(struct compiler *c, arguments_ty args)
 	return 1;
 }
 
+static int
+compiler_visit_kwonlydefaults(struct compiler *c, asdl_seq *kwonlyargs,
+	                      asdl_seq *kw_defaults)
+{
+	int i, default_count = 0;
+	for (i = 0; i < asdl_seq_LEN(kwonlyargs); i++) {
+		expr_ty arg = asdl_seq_GET(kwonlyargs, i);
+		expr_ty default_ = asdl_seq_GET(kw_defaults, i);
+		if (default_) {
+			ADDOP_O(c, LOAD_CONST, arg->v.Name.id, consts);
+			if (!compiler_visit_expr(c, default_)) {
+			    return -1;
+			}
+			default_count++;
+		}
+	}
+	return default_count;
+}
+
 static int
 compiler_function(struct compiler *c, stmt_ty s)
 {
@@ -1354,14 +1375,22 @@ compiler_function(struct compiler *c, stmt_ty s)
 	arguments_ty args = s->v.FunctionDef.args;
 	asdl_seq* decos = s->v.FunctionDef.decorators;
 	stmt_ty st;
-	int i, n, docstring;
+	int i, n, docstring, kw_default_count = 0, arglength;
 
 	assert(s->kind == FunctionDef_kind);
 
 	if (!compiler_decorators(c, decos))
 		return 0;
+	if (args->kwonlyargs) {
+		int res = compiler_visit_kwonlydefaults(c, args->kwonlyargs,
+						        args->kw_defaults);
+		if (res < 0)
+			return 0;
+		kw_default_count = res;
+	}
 	if (args->defaults)
 		VISIT_SEQ(c, expr, args->defaults);
+
 	if (!compiler_enter_scope(c, s->v.FunctionDef.name, (void *)s,
 				  s->lineno))
 		return 0;
@@ -1379,6 +1408,7 @@ compiler_function(struct compiler *c, stmt_ty s)
 	compiler_arguments(c, args);
 
 	c->u->u_argcount = asdl_seq_LEN(args->args);
+	c->u->u_kwonlyargcount = asdl_seq_LEN(args->kwonlyargs);
 	n = asdl_seq_LEN(s->v.FunctionDef.body);
 	/* if there was a docstring, we need to skip the first statement */
 	for (i = docstring; i < n; i++) {
@@ -1390,7 +1420,9 @@ compiler_function(struct compiler *c, stmt_ty s)
 	if (co == NULL)
 		return 0;
 
-	compiler_make_closure(c, co, asdl_seq_LEN(args->defaults));
+	arglength = asdl_seq_LEN(args->defaults);
+	arglength |= kw_default_count << 8;
+	compiler_make_closure(c, co, arglength);
 	Py_DECREF(co);
 
 	for (i = 0; i < asdl_seq_LEN(decos); i++) {
@@ -1485,6 +1517,7 @@ compiler_lambda(struct compiler *c, expr_ty e)
 {
 	PyCodeObject *co;
 	static identifier name;
+	int kw_default_count = 0, arglength;
 	arguments_ty args = e->v.Lambda.args;
 	assert(e->kind == Lambda_kind);
 
@@ -1494,6 +1527,12 @@ compiler_lambda(struct compiler *c, expr_ty e)
 			return 0;
 	}
 
+	if (args->kwonlyargs) {
+		int res = compiler_visit_kwonlydefaults(c, args->kwonlyargs,
+						        args->kw_defaults);
+		if (res < 0) return 0;
+		kw_default_count = res;
+	}
 	if (args->defaults)
 		VISIT_SEQ(c, expr, args->defaults);
 	if (!compiler_enter_scope(c, name, (void *)e, e->lineno))
@@ -1503,6 +1542,7 @@ compiler_lambda(struct compiler *c, expr_ty e)
 	compiler_arguments(c, args);
 	
 	c->u->u_argcount = asdl_seq_LEN(args->args);
+	c->u->u_kwonlyargcount = asdl_seq_LEN(args->kwonlyargs);
 	VISIT_IN_SCOPE(c, expr, e->v.Lambda.body);
 	ADDOP_IN_SCOPE(c, RETURN_VALUE);
 	co = assemble(c, 1);
@@ -1510,7 +1550,9 @@ compiler_lambda(struct compiler *c, expr_ty e)
 	if (co == NULL)
 		return 0;
 
-	compiler_make_closure(c, co, asdl_seq_LEN(args->defaults));
+	arglength = asdl_seq_LEN(args->defaults);
+	arglength |= kw_default_count << 8;
+	compiler_make_closure(c, co, arglength);
 	Py_DECREF(co);
 
 	return 1;
@@ -3791,7 +3833,8 @@ makecode(struct compiler *c, struct assembler *a)
 	Py_DECREF(consts);
 	consts = tmp;
 
-	co = PyCode_New(c->u->u_argcount, nlocals, stackdepth(c), flags,
+	co = PyCode_New(c->u->u_argcount, c->u->u_kwonlyargcount,
+			nlocals, stackdepth(c), flags,
 			bytecode, consts, names, varnames,
 			freevars, cellvars,
 			filename, c->u->u_name,

Python/graminit.c

@@ -146,14 +146,16 @@ static arc arcs_7_1[3] = {
 	{27, 5},
 	{0, 1},
 };
-static arc arcs_7_2[1] = {
+static arc arcs_7_2[3] = {
 	{19, 6},
+	{27, 7},
+	{0, 2},
 };
 static arc arcs_7_3[1] = {
-	{19, 7},
+	{19, 8},
 };
 static arc arcs_7_4[1] = {
-	{26, 8},
+	{26, 9},
 };
 static arc arcs_7_5[4] = {
 	{24, 1},
@@ -162,30 +164,41 @@ static arc arcs_7_5[4] = {
 	{0, 5},
 };
 static arc arcs_7_6[2] = {
-	{27, 9},
+	{27, 7},
 	{0, 6},
 };
-static arc arcs_7_7[1] = {
+static arc arcs_7_7[2] = {
-	{0, 7},
+	{19, 10},
-};
-static arc arcs_7_8[2] = {
-	{27, 5},
-	{0, 8},
-};
-static arc arcs_7_9[1] = {
 	{29, 3},
 };
-static state states_7[10] = {
+static arc arcs_7_8[1] = {
+	{0, 8},
+};
+static arc arcs_7_9[2] = {
+	{27, 5},
+	{0, 9},
+};
+static arc arcs_7_10[3] = {
+	{27, 7},
+	{25, 11},
+	{0, 10},
+};
+static arc arcs_7_11[1] = {
+	{26, 6},
+};
+static state states_7[12] = {
 	{3, arcs_7_0},
 	{3, arcs_7_1},
-	{1, arcs_7_2},
+	{3, arcs_7_2},
 	{1, arcs_7_3},
 	{1, arcs_7_4},
 	{4, arcs_7_5},
 	{2, arcs_7_6},
-	{1, arcs_7_7},
+	{2, arcs_7_7},
-	{2, arcs_7_8},
+	{1, arcs_7_8},
-	{1, arcs_7_9},
+	{2, arcs_7_9},
+	{3, arcs_7_10},
+	{1, arcs_7_11},
 };
 static arc arcs_8_0[2] = {
 	{19, 1},
@@ -1766,7 +1779,7 @@ static dfa dfas[83] = {
 	 "\000\010\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
 	{262, "parameters", 0, 4, states_6,
 	 "\000\040\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
-	{263, "varargslist", 0, 10, states_7,
+	{263, "varargslist", 0, 12, states_7,
 	 "\000\040\010\060\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},
 	{264, "fpdef", 0, 4, states_8,
 	 "\000\040\010\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"},

Python/import.c

@@ -67,9 +67,10 @@ extern time_t PyOS_GetLastModificationTime(char *, FILE *);
        Python 3000:   3000
        	              3010 (removed UNARY_CONVERT)
 		      3020 (added BUILD_SET)
+		      3030 (added keyword-only parameters)
 .
 */
-#define MAGIC (3020 | ((long)'\r'<<16) | ((long)'\n'<<24))
+#define MAGIC (3030 | ((long)'\r'<<16) | ((long)'\n'<<24))
 
 /* Magic word as global; note that _PyImport_Init() can change the
    value of this global to accommodate for alterations of how the

Python/marshal.c

@@ -349,6 +349,7 @@ w_object(PyObject *v, WFILE *p)
 		PyCodeObject *co = (PyCodeObject *)v;
 		w_byte(TYPE_CODE, p);
 		w_long(co->co_argcount, p);
+		w_long(co->co_kwonlyargcount, p);
 		w_long(co->co_nlocals, p);
 		w_long(co->co_stacksize, p);
 		w_long(co->co_flags, p);
@@ -815,6 +816,7 @@ r_object(RFILE *p)
 		}
 		else {
 			int argcount;
+			int kwonlyargcount;
 			int nlocals;
 			int stacksize;
 			int flags;
@@ -832,6 +834,7 @@ r_object(RFILE *p)
 			v = NULL;
 
 			argcount = r_long(p);
+			kwonlyargcount = r_long(p);
 			nlocals = r_long(p);
 			stacksize = r_long(p);
 			flags = r_long(p);
@@ -865,7 +868,8 @@ r_object(RFILE *p)
 				goto code_error;
 
 			v = (PyObject *) PyCode_New(
-					argcount, nlocals, stacksize, flags,
+					argcount, kwonlyargcount,
+					nlocals, stacksize, flags,
 					code, consts, names, varnames,
 					freevars, cellvars, filename, name,
 					firstlineno, lnotab);

Python/symtable.c

@@ -893,6 +893,17 @@ error:
 	} \
 }
 
+#define VISIT_KWONLYDEFAULTS(ST, KW_DEFAULTS) { \
+	int i = 0; \
+	asdl_seq *seq = (KW_DEFAULTS); /* avoid variable capture */ \
+	for (i = 0; i < asdl_seq_LEN(seq); i++) { \
+		expr_ty elt = (expr_ty)asdl_seq_GET(seq, i); \
+		if (!elt) continue; /* can be NULL */ \
+		if (!symtable_visit_expr((ST), elt)) \
+			return 0; \
+	} \
+}
+
 static int
 symtable_new_tmpname(struct symtable *st)
 {
@@ -910,6 +921,8 @@ symtable_new_tmpname(struct symtable *st)
 	return 1;
 }
 
+
+
 static int
 symtable_visit_stmt(struct symtable *st, stmt_ty s)
 {
@@ -919,6 +932,9 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
 			return 0;
 		if (s->v.FunctionDef.args->defaults)
 			VISIT_SEQ(st, expr, s->v.FunctionDef.args->defaults);
+		if (s->v.FunctionDef.args->kw_defaults)
+			VISIT_KWONLYDEFAULTS(st, 
+					   s->v.FunctionDef.args->kw_defaults);
 		if (s->v.FunctionDef.decorators)
 			VISIT_SEQ(st, expr, s->v.FunctionDef.decorators);
 		if (!symtable_enter_block(st, s->v.FunctionDef.name, 
@@ -1262,6 +1278,8 @@ symtable_visit_arguments(struct symtable *st, arguments_ty a)
 	*/
 	if (a->args && !symtable_visit_params(st, a->args, 1))
 		return 0;
+	if (a->kwonlyargs && !symtable_visit_params(st, a->kwonlyargs, 1))
+		return 0;
 	if (a->vararg) {
 		if (!symtable_add_def(st, a->vararg, DEF_PARAM))
 			return 0;

Tools/compiler/ast.txt

@@ -12,8 +12,8 @@
 Module: doc*, node
 Stmt: nodes!
 Decorators: nodes!
-Function: decorators&, name*, argnames*, defaults!, flags*, doc*, code
+Function: decorators&, name*, argnames*, defaults!, kwonlyargs*, flags*, doc*, code
-Lambda: argnames*, defaults!, flags*, code
+Lambda: argnames*, defaults!, kwonlyargs*, flags*, code
 Class: name*, bases!, doc*, code
 Pass: 
 Break: 
@@ -97,6 +97,7 @@ init(Lambda):
 init(GenExpr):
     self.argnames = ['.0']
     self.varargs = self.kwargs = None
+    self.kwonlyargs = ()
 
 init(GenExprFor):
     self.is_outmost = False