Overdue date syntax highlight

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "python/dateregex"]
+	path = python/dateregex
+	url = git@github.com:victal/dateregex.git

python/todo.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+import vim
+import os
+import sys
+from datetime import date
+
+dateregex_dir = os.path.join(vim.eval('s:script_dir'), 'dateregex')
+if os.path.isdir(dateregex_dir):
+    sys.path.insert(0, dateregex_dir)
+
+def add_due_date_syntax_highlight():
+    try: 
+        from dateregex import regex_date_before
+    except ImportError:
+        print("dateregex module not found. Overdue dates won't be highlighted")
+        return 
+
+    regex = regex_date_before(date.today())
+    regex = r'(^|<)due:%s(>|$)' % regex
+
+    vim.command("syntax match OverDueDate '\\v%s'" % regex)
+    vim.command("highlight  default  link  OverDueDate       Error")
+
+add_due_date_syntax_highlight()

syntax/todo.vim

@@ -52,6 +52,7 @@ highlight  default  link  TodoContext    Special
 
 if has('python')
     let b:curdir = expand('<sfile>:p:h')
+    let s:script_dir = b:curdir . "/../python/"
     execute "pyfile " . b:curdir . "/../python/todo.py"
 else
     echom "Your version of vim has no python support. Overdue dates won't be highlighted"