Add support for positional-only parameters in Python

Lib/idlelib/idle_test/test_calltip.py

@@ -59,21 +59,20 @@ def gtest(obj, out):
             self.assertEqual(signature(obj), out)
 
         if List.__doc__ is not None:
-            gtest(List, '(iterable=(), /)' + calltip._argument_positional
+            gtest(List, '(__iterable=())'
                   + '\n' + List.__doc__)
         gtest(list.__new__,
               '(*args, **kwargs)\n'
               'Create and return a new object.  '
               'See help(type) for accurate signature.')
         gtest(list.__init__,
-              '(self, /, *args, **kwargs)'
-              + calltip._argument_positional + '\n' +
+              '(__self, *args, **kwargs)'
+              + '\n' +
               'Initialize self.  See help(type(self)) for accurate signature.')
-        append_doc = (calltip._argument_positional
-                      + "\nAppend object to the end of the list.")
-        gtest(list.append, '(self, object, /)' + append_doc)
-        gtest(List.append, '(self, object, /)' + append_doc)
-        gtest([].append, '(object, /)' + append_doc)
+        append_doc = "\nAppend object to the end of the list."
+        gtest(list.append, '(__self, __object)' + append_doc)
+        gtest(List.append, '(__self, __object)' + append_doc)
+        gtest([].append, '(__object)' + append_doc)
 
         gtest(types.MethodType, "method(function, instance)")
         gtest(SB(), default_tip)

Lib/inspect.py

@@ -1918,6 +1918,7 @@ def _signature_strip_non_python_syntax(signature):
 
     current_parameter = 0
     OP = token.OP
+    NAME = token.NAME
     ERRORTOKEN = token.ERRORTOKEN
 
     # token stream always starts with ENCODING token, skip it
@@ -1939,14 +1940,17 @@ def _signature_strip_non_python_syntax(signature):
 
             if string == '/':
                 assert not skip_next_comma
-                assert last_positional_only is None
                 skip_next_comma = True
                 last_positional_only = current_parameter - 1
                 continue
 
+        if type == NAME and string.startswith('__'):
+            last_positional_only = current_parameter
+
         if (type == ERRORTOKEN) and (string == '$'):
             assert self_parameter is None
             self_parameter = current_parameter
+            last_positional_only = current_parameter
             continue
 
         if delayed_comma:
@@ -2192,7 +2196,7 @@ def _signature_from_function(cls, func):
     # parameters list (for correct order and defaults), it should be OK.
     return cls(parameters,
                return_annotation=annotations.get('return', _empty),
-               __validate_parameters__=is_duck_function)
+               _validate_parameters_=is_duck_function)
 
 
 def _signature_from_callable(obj, *,
@@ -2749,15 +2753,15 @@ class Signature:
     empty = _empty
 
     def __init__(self, parameters=None, *, return_annotation=_empty,
-                 __validate_parameters__=True):
+                 _validate_parameters_=True):
         """Constructs Signature from the given list of Parameter
         objects and 'return_annotation'.  All arguments are optional.
         """
 
         if parameters is None:
             params = OrderedDict()
         else:
-            if __validate_parameters__:
+            if _validate_parameters_:
                 params = OrderedDict()
                 top_kind = _POSITIONAL_ONLY
                 kind_defaults = False
@@ -3035,20 +3039,14 @@ def __repr__(self):
 
     def __str__(self):
         result = []
-        render_pos_only_separator = False
         render_kw_only_separator = True
         for param in self.parameters.values():
             formatted = str(param)
 
             kind = param.kind
 
-            if kind == _POSITIONAL_ONLY:
-                render_pos_only_separator = True
-            elif render_pos_only_separator:
-                # It's not a positional-only parameter, and the flag
-                # is set to 'True' (there were pos-only params before.)
-                result.append('/')
-                render_pos_only_separator = False
+            if kind == _POSITIONAL_ONLY and not formatted.startswith('__'):
+                    formatted = '__' + formatted
 
             if kind == _VAR_POSITIONAL:
                 # OK, we have an '*args'-like parameter, so we won't need
@@ -3065,11 +3063,6 @@ def __str__(self):
 
             result.append(formatted)
 
-        if render_pos_only_separator:
-            # There were only positional-only parameters, hence the
-            # flag was not reset to 'False'
-            result.append('/')
-
         rendered = '({})'.format(', '.join(result))
 
         if self.return_annotation is not _empty: