Added errorcodes.lookup() function.

ChangeLog

@@ -1,3 +1,7 @@
+2010-02-15  Daniele Varrazzo  <daniele.varrazzo@gmail.com>
+
+	* lib/errorcodes.py: Updated to PostgreSQL 8.4; added lookup() function.
+
 2010-02-12  Daniele Varrazzo  <daniele.varrazzo@gmail.com>
 
 	* Stop the loop variable used to create __all__ leaking in the module.

lib/errorcodes.py

@@ -29,6 +29,22 @@ This module contains symbolic names for all PostgreSQL error codes.
 #   http://www.postgresql.org/docs/8.4/static/errcodes-appendix.html
 #
 
+def lookup(code, _cache={}):
+    """Lookup a code error and return its symbolic name.
+
+    Raise KeyError if the code is not found.
+    """
+    if _cache:
+        return _cache[code]
+
+    # Generate the lookup map at first usage.
+    for k, v in globals().iteritems():
+        if isinstance(v, str) and len(v) in (2, 5):
+            _cache[v] = k
+
+    return lookup(code)
+
+
 # autogenerated data: do not edit below this point.
 
 # Error classes