1 files changed, 7 insertions, 1 deletions
diff --git a/Lib/sre.py b/Lib/sre.py
index 7969723..a33e34e 100644
--- a/Lib/sre.py
+++ b/Lib/sre.py
@@ -188,12 +188,18 @@ def template(pattern, flags=0):
     "Compile a template pattern, returning a pattern object"
     return _compile(pattern, flags|T)
 
+_alphanum = {}
+for c in 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890':
+    _alphanum[c] = 1
+del c
+
 def escape(pattern):
     "Escape all non-alphanumeric characters in pattern."
     s = list(pattern)
+    alphanum = _alphanum
     for i in range(len(pattern)):
         c = pattern[i]
-        if not ("a" <= c <= "z" or "A" <= c <= "Z" or "0" <= c <= "9"):
+        if c not in alphanum:
             if c == "\000":
                 s[i] = "\\000"
             else: