Script to be run as a TextExpander snippet that creates a due date tag from a natural language date string.

teDuedate.py

#!/usr/local/bin/python

# Requires parsedatetime module: 
# https://github.com/bear/parsedatetime

import parsedatetime as pdt

natLangDateStr = "%filltext:name=date:default=today%"
dt = pdt.Calendar().parse(natLangDateStr)[0]

formattedDate = "{month}-{day}-{year}".format(month=dt.tm_mon,
    day=dt.tm_mday, year=dt.tm_year)

print "@due(" + formattedDate + ")"