--- a/__init__.py	Tue Jun 10 18:33:15 2008 -0400
+++ b/__init__.py	Tue Jun 10 20:02:25 2008 -0400
@@ -1,70 +1,10 @@
 import filetensor
 import nnet_ops
+import version
 
 from lookup_list import LookupList
 
-
-
-import subprocess as _subprocess
-import imp as _imp
 def __src_version__():
-    """Return compact identifier of module code.
-
-    @return: compact identifier of module code.
-    @rtype: string
-
-    @note: This function tries to establish that the source files and the repo
-    are syncronized.  It raises an Exception if there are un-tracked '.py'
-    files, or if there are un-committed modifications.  This implementation uses
-    "hg id" to establish this.  The code returned by "hg id" is not affected by
-    hg pull, but pulling might remove the " tip" string which might have
-    appeared.  This implementation ignores the  " tip" information, and only
-    uses the code.
-
-    @note: This implementation is assumes that the import directory is under
-    version control by mercurial.
-
-    """
-    #
-    # NOTE
-    #
-    # If you find bugs in this function, please update the __src_version__
-    # function in theano, pylearn, and email either theano-dev or pylearn-dev so
-    # that people can update their experiment dirs (the output of this function
-    # is meant to be hard-coded in external files).
-    #
+    #todo - this is vulnerable to the bug in theano ticket #160
+    return version.src_version(__name__)
 
-    if not hasattr(__src_version__, 'rval'):
-        #print 'name:', __name__
-        location = _imp.find_module(__name__)[1]
-        #print 'location:', location
-
-        status = _subprocess.Popen(('hg','st'),cwd=location,stdout=_subprocess.PIPE).communicate()[0]
-        #status_codes = [line[0] for line in  if line and line[0] != '?']
-        for line in status.split('\n'):
-            if not line: continue
-            if line[0] != '?':
-                raise Exception('Uncommitted modification to "%s" in %s (%s)'
-                        %(line[2:], __name__,location))
-            if line[0] == '?' and line[-3:] == '.py':
-                raise Exception('Untracked file "%s" in %s (%s)'
-                        %(line[2:], __name__, location))
-
-        hg_id = _subprocess.Popen(('hg','id'),cwd=location,stdout=_subprocess.PIPE).communicate()[0]
-
-        #This asserts my understanding of hg id return values
-        # There is mention in the doc that it might return two parent hash codes
-        # but I've never seen it, and I dont' know what it means or how it is
-        # formatted.
-        tokens = hg_id.split(' ')
-        assert len(tokens) <= 2
-        assert len(tokens) >= 1
-        assert tokens[0][-1] != '+' # the trailing + indicates uncommitted changes
-        if len(tokens) == 2:
-            assert tokens[1] == 'tip\n'
-
-        __src_version__.rval = tokens[0]
-
-    return __src_version__.rval
-
-

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/version.py	Tue Jun 10 20:02:25 2008 -0400
@@ -0,0 +1,68 @@
+import subprocess as _subprocess
+import imp as _imp
+
+_cache = {}
+
+def src_version(module_name):
+    """Return compact identifier of module code.
+
+    @return: compact identifier of module code.
+    @rtype: string
+
+    @note: This function tries to establish that the source files and the repo
+    are syncronized.  It raises an Exception if there are un-tracked '.py'
+    files, or if there are un-committed modifications.  This implementation uses
+    "hg id" to establish this.  The code returned by "hg id" is not affected by
+    hg pull, but pulling might remove the " tip" string which might have
+    appeared.  This implementation ignores the  " tip" information, and only
+    uses the code.
+
+    @note: This implementation is assumes that the import directory is under
+    version control by mercurial.
+
+    """
+    #
+    # NOTE
+    #
+    # If you find bugs in this function, please update the __src_version__
+    # function in theano, pylearn, and email either theano-dev or pylearn-dev so
+    # that people can update their experiment dirs (the output of this function
+    # is meant to be hard-coded in external files).
+    #
+
+    if module_name not in _cache:
+
+        location = _imp.find_module(module_name)[1]
+        #print 'location:', location
+
+        status = _subprocess.Popen(('hg','st'),cwd=location,stdout=_subprocess.PIPE).communicate()[0]
+        #TODO: check that the process return code is 0 (ticket #45)
+
+        #status_codes = [line[0] for line in  if line and line[0] != '?']
+        for line in status.split('\n'):
+            if not line: continue
+            if line[0] != '?':
+                raise Exception('Uncommitted modification to "%s" in %s (%s)'
+                        %(line[2:], __name__,location))
+            if line[0] == '?' and line[-3:] == '.py':
+                raise Exception('Untracked file "%s" in %s (%s)'
+                        %(line[2:], __name__, location))
+
+        hg_id = _subprocess.Popen(('hg','id'),cwd=location,stdout=_subprocess.PIPE).communicate()[0]
+
+        #This asserts my understanding of hg id return values
+        # There is mention in the doc that it might return two parent hash codes
+        # but I've never seen it, and I dont' know what it means or how it is
+        # formatted.
+        tokens = hg_id.split(' ')
+        assert len(tokens) <= 2
+        assert len(tokens) >= 1
+        assert tokens[0][-1] != '+' # the trailing + indicates uncommitted changes
+        if len(tokens) == 2:
+            assert tokens[1] == 'tip\n'
+
+        _cache[module_name] = tokens[0]
+
+    return _cache[module_name]
+
+