--- a/.hgignore	Thu Feb 06 21:40:33 2014 -0800
+++ b/.hgignore	Thu Feb 06 22:00:32 2014 -0800
@@ -2,6 +2,7 @@
 venv
 node_modules
 wikked/static
+wikked/__version__.py
 dist
 build
 *.pyc

--- a/setup.py	Thu Feb 06 21:40:33 2014 -0800
+++ b/setup.py	Thu Feb 06 22:00:32 2014 -0800
@@ -1,7 +1,8 @@
 import os
 import os.path
+import time
+import subprocess
 from setuptools import setup, find_packages
-from wikked import VERSION
 
 
 def read(fname):
@@ -9,14 +10,58 @@
         return fp.read()
 
 
-#TODO: get the build version from the source control revision.
-BUILD_VERSION = 4
-FULL_VERSION = '%s.%s' % (VERSION, BUILD_VERSION)
+def runcmd(cmd):
+    p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
+                         stderr=subprocess.PIPE)
+    out, err = p.communicate()
+    return out, err
+
+
+# Figure out the version.
+# (this is loosely based on what Mercurial does)
+try:
+    if os.path.isdir('.hg'):
+        cmd = ['hg', 'log', '-r', '.', '--template', '{tags}\n']
+        tags, err = runcmd(cmd)
+        versions = [t for t in tags.split() if t[0].isdigit()]
+
+        cmd = ['hg', 'id', '-i']
+        hgid, err = runcmd(cmd)
+        hgid = hgid.strip()
+
+        if versions:
+            # Use tag found at the current revision. Add dirty flag if any.
+            version = versions[-1]
+            if hgid.endswith('+'):
+                version += '+'
+        else:
+            # Use latest tag.
+            cmd = ['hg', 'parents', '--template', '{latesttag}+{latesttagdistance}-']
+            version, err = runcmd(cmd)
+            version += hgid
+        if version.endswith('+'):
+            version += time.strftime('%Y%m%d')
+except OSError:
+    # Mercurial isn't installed, or not in the PATH.
+    version = None
+
+if version:
+    f = open("wikked/__version__.py", "w")
+    f.write('# this file is autogenerated by setup.py\n')
+    f.write('version = "%s"\n' % version)
+    f.close()
+
+
+try:
+    from wikked import __version__
+    version = __version__.version
+except ImportError:
+    version = 'unknown'
 
 
 setup(
         name='Wikked',
-        version=FULL_VERSION,
+        version=version,
         description=("A wiki engine entirely managed with text files "
             "stored in a revision control system."),
         author='Ludovic Chabant',

--- a/wikked/__init__.py	Thu Feb 06 21:40:33 2014 -0800
+++ b/wikked/__init__.py	Thu Feb 06 22:00:32 2014 -0800
@@ -1,2 +1,1 @@
-VERSION = '0.1.0'