diff --git a/jsvn b/jsvn
index 66447d0..a78ac93 100755
--- a/jsvn
+++ b/jsvn
@@ -12,6 +12,7 @@ import time
 from subprocess import *
 import traceback
 import datetime
+import types
 
 STATUS_LINE_REGEX = r'[ACDIMRX?!~ ][CM ][L ][+ ][SX ][KOTB ]..(.+)'
 
@@ -109,17 +110,6 @@ def get_config(svn):
 
     return config
 
-def apply_aliases(config, argv):
-    if not argv[0] in config['aliases']:
-        return argv
-    alias = config['aliases'][argv[0]]
-    if type(alias) == str:
-        return [alias] + argv[1:]
-    elif type(alias) == list:
-        return alias + argv[1:]
-    sys.stderr.write('Unsupported type for alias "%s"\n' % alias)
-    return argv
-
 ###########################################################################
 # Utility Functions                                                       #
 ###########################################################################
@@ -1033,23 +1023,38 @@ def url(argv, svn, out):
 ###########################################################################
 # Main                                                                    #
 ###########################################################################
-def main(argv):
+def do_cmd(argv, realsvn, config, expand=True):
     global using_color
 
-    realsvn = find_in_path('svn')
-    config = get_config(realsvn)
-    if config['svn']:
-        realsvn = config['svn']
+    if len(argv) == 0:
+        Popen([realsvn]).wait()
+        return
+
+    if expand and (argv[0] in config['aliases']):
+        # expand aliases
+        orig_subcommand = argv[0]
+        alias = config['aliases'][argv[0]]
+        if hasattr(alias, '__call__'):
+            # alias is a python function, call it
+            alias(argv)
+            return
+        elif type(alias) == types.StringType:
+            argv = [alias] + argv[1:]
+        elif type(alias) == types.ListType:
+            argv = alias + argv[1:]
+        else:
+            sys.stderr.write('Unsupported type for alias "%s"\n' % alias)
+
+        # after expanding the alias, check if it is an external
+        # command to launch
+        if argv[0].startswith('!'):
+            # execute an external program
+            argv[0] = argv[0][1:]       # strip leading '!'
+            argv = [argv[0], orig_subcommand] + argv[1:]
+            Popen(argv, shell=True).wait()
+            return
+
     out = sys.stdout
-    orig_subcommand = argv[0] if len(argv) > 0 else ''
-    if len(argv) > 0:
-        argv = apply_aliases(config, argv)
-    if len(argv) > 0 and argv[0].startswith('!'):
-        # execute an external program
-        argv[0] = argv[0][1:]       # strip leading '!'
-        argv = [argv[0], orig_subcommand] + argv[1:]
-        Popen(argv, shell=True).wait()
-        return 0
     using_pager = False
     using_color = sys.stdout.isatty() and config['use_color']
     if sys.stdout.isatty() and config['use_pager']:
@@ -1091,22 +1096,31 @@ def main(argv):
             'stash': stash,
             }
 
-    do_normal_exec = True
-    if len(argv) >= 1:
-        if argv[0] in handlers:
-            r = handlers[argv[0]](argv, realsvn, out)
-            if r == RET_OK or r == RET_ERR:
-                do_normal_exec = False
-        elif argv[0].startswith('__'):
-            # allow double-underscore commands to execute the native
-            # subversion command (e.g. "__st")
-            argv[0] = argv[0][2:]
+    do_native_exec = True
+    if argv[0] in handlers:
+        r = handlers[argv[0]](argv, realsvn, out)
+        if r == RET_OK or r == RET_ERR:
+            do_native_exec = False
+    elif argv[0].startswith('__'):
+        # allow double-underscore commands to execute the native
+        # subversion command (e.g. "__st")
+        argv[0] = argv[0][2:]
 
-    if do_normal_exec:
+    if do_native_exec:
         Popen([realsvn] + argv, stdout=out).wait()
+
     if using_pager:
         out.close()
         pager_proc.wait()
+
+def main(argv):
+    realsvn = find_in_path('svn')
+    config = get_config(realsvn)
+    if config['svn']:
+        realsvn = config['svn']
+
+    do_cmd(argv, realsvn, config)
+
     return 0
 
 if __name__ == "__main__":