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

[etc/vim.git] / blib2to3 / pgen2 / grammar.py

diff --git a/blib2to3/pgen2/grammar.py b/blib2to3/pgen2/grammar.py
index c00cb2248d5676092c82d9da3f67d9b2f54f67ad..32d1d8b7226e3b4b8f27068d70628c12cdf42fa6 100644 (file)
--- a/blib2to3/pgen2/grammar.py
+++ b/blib2to3/pgen2/grammar.py
@@ -13,8 +13,9 @@ fallback token code OP, but the parser needs the actual token code.
 """
 
 # Python imports
 """
 
 # Python imports

-import collections
+import os

 import pickle
 import pickle

+import tempfile

 
 # Local imports
 from . import token
 
 # Local imports
 from . import token


@@ -84,11 +85,14 @@ class Grammar(object):
         self.tokens = {}
         self.symbol2label = {}
         self.start = 256
         self.tokens = {}
         self.symbol2label = {}
         self.start = 256

+        # Python 3.7+ parses async as a keyword, not an identifier
+        self.async_keywords = False

 
     def dump(self, filename):
         """Dump the grammar tables to a pickle file."""
 
     def dump(self, filename):
         """Dump the grammar tables to a pickle file."""

-        with open(filename, "wb") as f:
+        with tempfile.NamedTemporaryFile(dir=os.path.dirname(filename), delete=False) as f:

             pickle.dump(self.__dict__, f, pickle.HIGHEST_PROTOCOL)
             pickle.dump(self.__dict__, f, pickle.HIGHEST_PROTOCOL)

+        os.replace(f.name, filename)

 
     def load(self, filename):
         """Load the grammar tables from a pickle file."""
 
     def load(self, filename):
         """Load the grammar tables from a pickle file."""


@@ -111,6 +115,7 @@ class Grammar(object):
         new.labels = self.labels[:]
         new.states = self.states[:]
         new.start = self.start
         new.labels = self.labels[:]
         new.states = self.states[:]
         new.start = self.start

+        new.async_keywords = self.async_keywords

         return new
 
     def report(self):
         return new
 
     def report(self):