Changed the way how parameters are being built

The old way consisted in having the parameter names, their
defaults and their annotations separated in different components
of the Arguments node. We introduced a new Param node, which holds
the name of a parameter, its default value and its annotation.
If any of the last two values are missing, then that slot will be
filled with a new node kind, Empty, which is used for specifying the
lack of something (None could have been used instead, but that means having
non-AST nodes in the Arguments node).
We're also having support for positional only arguments, for the moment
only in raw_building.

Close #215

1 files changed, 17 insertions, 13 deletions

diff --git a/astroid/tree/scoped_nodes.py b/astroid/tree/scoped_nodes.py
index d04b549b..6744ec82 100644
--- a/astroid/tree/scoped_nodes.py
+++ b/astroid/tree/scoped_nodes.py
@@ -686,7 +686,7 @@ class CallSite(object):
             pass
 
         # Too many arguments given and no variable arguments.
-        if len(self.positional_arguments) > len(self._funcnode.args.args):
+        if len(self.positional_arguments) > len(self._funcnode.args.positional_and_keyword):
             if not self._funcnode.args.vararg:
                 raise exceptions.InferenceError('Too many positional arguments '
                                                 'passed to {func!r} that does '
@@ -694,10 +694,10 @@ class CallSite(object):
                                                 call_site=self, func=self._funcnode,
                                                 arg=name, context=context)
 
-        positional = self.positional_arguments[:len(self._funcnode.args.args)]
-        vararg = self.positional_arguments[len(self._funcnode.args.args):]
+        positional = self.positional_arguments[:len(self._funcnode.args.positional_and_keyword)]
+        vararg = self.positional_arguments[len(self._funcnode.args.positional_and_keyword):]
         argindex = self._funcnode.args.find_argname(name)[0]
-        kwonlyargs = set(arg.name for arg in self._funcnode.args.kwonlyargs)
+        kwonlyargs = set(arg.name for arg in self._funcnode.args.keyword_only)
         kwargs = {
             key: value for key, value in self.keyword_arguments.items()
             if key not in kwonlyargs
@@ -707,8 +707,8 @@ class CallSite(object):
         # if the missing positional arguments were passed
         # as keyword arguments and if so, place them into the
         # positional args list.
-        if len(positional) < len(self._funcnode.args.args):
-            for func_arg in self._funcnode.args.args:
+        if len(positional) < len(self._funcnode.args.positional_and_keyword):
+            for func_arg in self._funcnode.args.positional_and_keyword:
                 if func_arg.name in kwargs:
                     arg = kwargs.pop(func_arg.name)
                     positional.append(arg)
@@ -748,7 +748,7 @@ class CallSite(object):
             except IndexError:
                 pass
 
-        if self._funcnode.args.kwarg == name:
+        if self._funcnode.args.kwarg and self._funcnode.args.kwarg.name == name:
             # It wants all the keywords that were passed into
             # the call site.
             if self.has_invalid_keywords():
@@ -769,7 +769,7 @@ class CallSite(object):
             kwarg.postinit(keys, values)
             return iter((kwarg, ))
 
-        elif self._funcnode.args.vararg == name:
+        if self._funcnode.args.vararg and self._funcnode.args.vararg.name == name:
             # It wants all the args that were passed into
             # the call site.
             if self.has_invalid_arguments():
@@ -813,7 +813,9 @@ class LambdaFunctionMixin(QualifiedNameMixin, base.FilterStmtsMixin):
         return CallSite(self, args, keywords)
 
     def scope_lookup(self, node, name, offset=0):
-        if node in self.args.defaults or node in self.args.kw_defaults:
+        
+        if node in itertools.chain((self.args.positional_and_keyword,
+                                    self.args.keyword_only)):
             frame = self.parent.frame()
             # line offset to avoid that def func(f=func) resolve the default
             # value to the defined function
@@ -825,14 +827,16 @@ class LambdaFunctionMixin(QualifiedNameMixin, base.FilterStmtsMixin):
 
     def argnames(self):
         """return a list of argument names"""
-        if self.args.args: # maybe None with builtin functions
-            names = _rec_get_names(self.args.args)
+        if self.args.positional_and_keyword: # maybe None with builtin functions
+            names = _rec_get_names(self.args.positional_and_keyword)
         else:
             names = []
         if self.args.vararg:
-            names.append(self.args.vararg)
+            names.append(self.args.vararg.name)
         if self.args.kwarg:
-            names.append(self.args.kwarg)
+            names.append(self.args.kwarg.name)
+        if self.args.keyword_only:
+            names.extend([arg.name for arg in self.keyword_only])
         return names
 
     def callable(self):