From: andrew cooke <andrew@...>

Date: Sun, 23 Jun 2013 04:40:29 -0400

I've modified the way that Python parses dates to make it significantly more flexible. As a consequence, SimpleDate can now parse dates mure more quickly. For example, all these dates are parsed by a single template (before they would have required evaluating different templates in turn): >>> SimpleDate('2013-06-23').normalized SimpleDate('2013-06-23 04:00:00.000000 UTC', tz='UTC') >>> SimpleDate('20130623T0420').normalized SimpleDate('2013-06-23 08:20:00.000000 UTC', tz='UTC') >>> SimpleDate('2013/06/23 4:20 UTC').normalized SimpleDate('2013-06-23 04:20:00.000000 UTC', tz='UTC') (the 4 hours shift on parsing the first two is because by default we use the locale timezone, which is CLT). The extension to Python's date templates is conservative in that: - existing symbols have the same meaning as before - the construction of a date from the parsed data uses exactly the same algorithm as before What has been added is the ability to: - Specify alternatives. For example, {%Z|%z} will match either of the two timezone formats. - Specify optional values. For example %Y-%m-%d{ %H:%M:%S}? makes the time part optional. As you can see from the examples, the extension uses familiar regexp syntax, but with brackets instead of parentheses (parens sometimes occur in date expressions, so this reduces the need for escaping). What's particularly cute about the implementation is that parsing will "disambiguate" the template. You get back from the parser an equivalent template that matches (more or less) the parsed input, without the extra features. This allows you to use display the date in the original format. For example: >>> strptime('12:34', '{%H:}?%M') ((1900, 1, 1, 12, 34, 0, 0, 1, -1, None, None), 0, '%H:%M') >>> strptime('34', '{%H:}?%M') ((1900, 1, 1, 0, 34, 0, 0, 1, -1, None, None), 0, '%M') in the second case no hours were given and the resturned format (final value in result) is only for the minutes. Simple Date is available at: https://github.com/andrewcooke/simple-date https://pypi.python.org/pypi/simple-date The source that implements this can be seen here: https://github.com/andrewcooke/simple-date/blob/master/src/simpledate/fmt.py Andrew