Simple expression language implementing date arithmetic for Python.
Sure, datetime.timedelta is nice, but code to do simple date arithmetic shouldn't be that hard. Further, the logic for implementing date math "with rounding" (e.g. NOW/DAY - 14DAYS, meaning 14 days since the start of today) is a little bit tricky, and reads much better as a string.
This module is implemented using PLY. It therefore has some basic syntax checking and the beginnings of a REPL for testing. It also means that it uses a LALR table-based parser which is auto-generated in memory from some definitions in datemath_yacc.py.
Usage:
>>> from datemath import datemath
>>> datemath("NOW")
datetime.datetime(2012, 2, 26, 21, 56, 52, 489700)
>>> datemath("NOW - 1MONTH")
datetime.datetime(2012, 1, 26, 21, 57, 41, 142164)
>>> datemath("NOW/MONTH - 7DAYS")
datetime.datetime(2012, 12, 25, 0, 0, 0)- Solr Date Format used as inspiration
- PLY used for the lexer and parser