get version number from package version instead of rewriting the __init__.py file

python/lammps/__init__.py

@@ -13,6 +13,37 @@ from .core import *
 from .data import *
 from .pylammps import *
 
-# automatically updated during installation
+# convert module string version to numeric version
+def get_version_number():
+    import re
+    from sys import version_info
+    vstring = None
+    if version_info.major == 3 and version_info.minor >= 8:
+        from importlib.metadata import version
+        try:
+            vstring = version('lammps')
+        except: pass
+    else:
+        from pkg_resources import get_distribution
+        try:
+            vstring = get_distribution('lammps').version
+        except: pass
 
-__version__ = 0
+    if not vstring:
+        return 0
+
+    vregex = re.compile(r"([0-9]+)([A-Za-z]+)(2[0-9]+)")
+    m = vregex.match(vstring)
+
+    if (m):
+        month2num = { 'Jan' : 1, 'Feb' : 2, 'Mar' : 3, 'Apr' : 4, 'May' : 5, 'Jun' : 6,
+                'Jul' : 7, 'Aug' : 8, 'Sep' : 9, 'Oct' : 10, 'Nov' : 11, 'Dec' : 12 }
+        try:
+            vernum = int(m.group(3))*10000
+            vernum += month2num[m.group(2)]*100
+            vernum += int(m.group(1))
+        except:
+            exit('Failure to parse version string: %s' % verstr)
+    return vernum
+
+__version__ = get_version_number()