Highlight keyword arguments in python call

The highlight group name: semshiKeywordArgument.
(see https://docs.python.org/3/glossary.html#term-argument)

By default the hlgroup is linked to `@parameter.python` to ensure better
compatibility with treesitter.

README.md

@@ -99,6 +99,7 @@ hi semshiGlobal          ctermfg=214 guifg=#ffaf00
 hi semshiImported        ctermfg=214 guifg=#ffaf00 cterm=bold gui=bold
 hi semshiParameter       ctermfg=75  guifg=#5fafff
 hi semshiParameterUnused ctermfg=117 guifg=#87d7ff cterm=underline gui=underline
+hi def link semshiKeywordArgument @parameter.python
 hi semshiFree            ctermfg=218 guifg=#ffafd7
 hi semshiBuiltin         ctermfg=207 guifg=#ff5fff
 hi semshiAttribute       ctermfg=49  guifg=#00ffaf

plugin/semshi.vim

@@ -90,11 +90,13 @@ function! semshi#buffer_wipeout()
 endfunction
 
 function! semshi#init()
+    " Also update README.md
     hi def semshiLocal           ctermfg=209 guifg=#ff875f
     hi def semshiGlobal          ctermfg=214 guifg=#ffaf00
     hi def semshiImported        ctermfg=214 guifg=#ffaf00 cterm=bold gui=bold
     hi def semshiParameter       ctermfg=75  guifg=#5fafff
     hi def semshiParameterUnused ctermfg=117 guifg=#87d7ff cterm=underline gui=underline
+    hi def link semshiKeywordArgument   @parameter.python
     hi def semshiFree            ctermfg=218 guifg=#ffafd7
     hi def semshiBuiltin         ctermfg=207 guifg=#ff5fff
     hi def semshiAttribute       ctermfg=49  guifg=#00ffaf

rplugin/python3/semshi/node.py

@@ -16,6 +16,7 @@ def group(s):
 GLOBAL = group('global')
 PARAMETER = group('parameter')
 PARAMETER_UNUSED = group('parameterUnused')
+KEYWORD = group('keywordArgument')
 SELF = group('self')
 IMPORTED = group('imported')
 LOCAL = group('local')

rplugin/python3/semshi/visitor.py

@@ -5,7 +5,7 @@
 from token import NAME, OP
 from tokenize import tokenize
 
-from .node import ATTRIBUTE, IMPORTED, PARAMETER_UNUSED, SELF, Node
+from .node import ATTRIBUTE, IMPORTED, PARAMETER_UNUSED, SELF, KEYWORD, Node
 from .util import debug_time
 
 # Node types which introduce a new scope
@@ -89,6 +89,8 @@ def visit(self, node):
             self._visit_except(node)
         elif type_ in (ast.Import, ast.ImportFrom):
             self._visit_import(node)
+        elif type_ is ast.keyword:
+            self._visit_keyword(node)
         elif type_ is ast.arg:
             self._visit_arg(node)
         elif type_ in FUNCTION_BLOCKS:
@@ -99,7 +101,7 @@ def visit(self, node):
         elif type_ in (ast.Global, ast.Nonlocal):
             keyword = 'global' if type_ is ast.Global else 'nonlocal'
             self._visit_global_nonlocal(node, keyword)
-        elif type_ is ast.keyword:
+        else:
             pass
 
         if type_ in (ast.FunctionDef, ast.ClassDef, ast.AsyncFunctionDef):
@@ -203,6 +205,25 @@ def _visit_class_meta(self, node):
             self.visit(keyword)
         del node.keywords
 
+    def _visit_keyword(self, node: ast.keyword):
+        """Visit keyword argument in a function call."""
+        if node.arg:
+            # keyword=argument: highlight keyword
+            try:
+                lineno = node.lineno
+                col_offset = node.col_offset
+            except AttributeError:
+                # Python < 3.9 does not have node.lineno, etc.
+                # No highlight can be provided for keyworda rguments.
+                return
+            self.nodes.append(Node(
+                node.arg, lineno, col_offset, self._cur_env,
+                hl_group=KEYWORD
+            ))
+        else:
+            # This is probably (**kwargs), do nothing
+            pass
+
     def _visit_args(self, node):
         """Visit function arguments."""
         # We'd want to visit args.posonlyargs, but it appears an internal bug

test/test_parser.py

@@ -6,7 +6,7 @@
 import pytest
 
 from semshi import parser
-from semshi.node import (ATTRIBUTE, BUILTIN, FREE, GLOBAL, IMPORTED, LOCAL,
+from semshi.node import (ATTRIBUTE, BUILTIN, FREE, GLOBAL, IMPORTED, KEYWORD, LOCAL,
                          PARAMETER, PARAMETER_UNUSED, SELF, UNRESOLVED, Node,
                          group)
 from semshi.parser import Parser, UnparsableError
@@ -18,6 +18,9 @@
 # but as GLOBAL in Python 3.8.
 MODULE_FUNC = GLOBAL if sys.version_info >= (3, 8) else LOCAL
 
+filternone = lambda lst: [x for x in lst if x is not None]
+py39 = lambda x: (x if sys.version_info >= (3, 9) else None)
+
 
 def test_group():
     assert group('foo') == 'semshiFoo'
@@ -172,9 +175,9 @@ def func2(j=k):
     func(x, y=p, **z)
     ''')
     root = make_tree(names)
-    assert root['names'] == [
-        'e', 'h', 'func', 'k', 'func2', 'func', 'x', 'p', 'z'
-    ]
+    assert root['names'] == filternone([
+        'e', 'h', 'func', 'k', 'func2', 'func', 'x', py39('y'), 'p', 'z'
+    ])
     assert root['listcomp']['names'] == ['g', 'g']
     assert root['func']['names'] == ['a', 'b', 'c', 'd', 'f', 'i']
     assert root['func2']['names'] == ['j']
@@ -189,7 +192,7 @@ def f():
             a
     ''')
     root = make_tree(names)
-    assert root['names'] == ['a', 'A', 'x', 'z']
+    assert root['names'] == filternone(['a', 'A', 'x', py39('y'), 'z'])
 
 
 def test_import_scopes_and_positions():
@@ -482,9 +485,10 @@ async def C():
         pass
     ''')
     root = make_tree(names)
-    assert root['names'] == [
-        'd1', 'a', 'c', 'A', 'd2', 'x', 'z', 'B', 'd3', 'C'
-    ]
+    assert root['names'] == filternone([
+        'd1', 'a', py39('b'), 'c', 'A',
+        'd2', 'x', py39('y'), 'z', 'B', 'd3', 'C'
+    ])
 
 def test_global_builtin():
     """A builtin name assigned globally should be highlighted as a global, not
@@ -827,6 +831,17 @@ def test_posonlyargs_with_annotation():
     assert [n.hl_group for n in names] == [MODULE_FUNC, UNRESOLVED, PARAMETER_UNUSED]
 
 
+def test_keyword_arguments():
+    names = parse('foo(x, y, kwarg1=z, bar=dict(value=1))')
+    assert [n.name for n in names] == filternone([
+        'foo', 'x', 'y', py39('kwarg1'), 'z',
+        py39('bar'), 'dict', py39('value'),
+    ])
+    for n in names:
+        if n.name == 'kwarg1' or n.name == 'value':
+            assert n.hl_group == KEYWORD
+
+
 @pytest.mark.skipif('sys.version_info < (3, 8)')
 @pytest.mark.parametrize("enable_pep563", (False, True))
 def test_postponed_evaluation_of_annotations_pep563(enable_pep563):