# HG changeset patch
# User dukebody <dukebody@gmail.com>
# Date 1255993113 -7200
# Node ID 40e41b3eeaf6c881fa2f284787e64c71b307f5a3
# Parent  86073756fe77b8191a6b460f062ca4c55279d16c
Add sysargs checker.

diff -r 86073756fe77 -r 40e41b3eeaf6 web/hgbook/converter.py
--- a/web/hgbook/converter.py	Mon Oct 19 20:01:15 2009 +0200
+++ b/web/hgbook/converter.py	Tue Oct 20 00:58:33 2009 +0200
@@ -17,11 +17,14 @@
 sel = CSSSelector('p, pre, h1, table.equation')
 body = CSSSelector('body')
 
-filename = args[0]
+try:
+    filename = args[0]
+except IndexError:
+    raise IndexError("Usage: %s <path-to-html-file>" % __file__)
+
 tree = etree.parse(filename, html.HTMLParser())
 root = tree.getroot()
 
-
 body(root)[0].set('id', doc_id)
 
 for element in sel(root):