minor performance improvement (~2% speedup in unit tests) (#858)

[etc/vim.git] / blib2to3 / pygram.py

diff --git a/blib2to3/pygram.py b/blib2to3/pygram.py
index 725fb699bf62410838f08b95afc0d0d077d03e5d..f6ef00154e13c2fedae946310d9f73e6e576be0f 100644 (file)
--- a/blib2to3/pygram.py
+++ b/blib2to3/pygram.py
@@ -33,6 +33,7 @@ def initialize(cache_dir=None):
     global python_grammar
     global python_grammar_no_print_statement
     global python_grammar_no_print_statement_no_exec_statement
+    global python_grammar_no_print_statement_no_exec_statement_async_keywords
     global python_symbols
     global pattern_grammar
     global pattern_symbols
@@ -47,11 +48,17 @@ def initialize(cache_dir=None):
     python_grammar_no_print_statement = python_grammar.copy()
     del python_grammar_no_print_statement.keywords["print"]
 
-    # Python 3
+    # Python 3.0-3.6
     python_grammar_no_print_statement_no_exec_statement = python_grammar.copy()
     del python_grammar_no_print_statement_no_exec_statement.keywords["print"]
     del python_grammar_no_print_statement_no_exec_statement.keywords["exec"]
 
+    # Python 3.7+
+    python_grammar_no_print_statement_no_exec_statement_async_keywords = (
+        python_grammar_no_print_statement_no_exec_statement.copy()
+    )
+    python_grammar_no_print_statement_no_exec_statement_async_keywords.async_keywords = True
+
     pattern_grammar = driver.load_packaged_grammar("blib2to3", _PATTERN_GRAMMAR_FILE,
                                                    cache_dir)
     pattern_symbols = Symbols(pattern_grammar)