For some reason I started maintaining PHP's strtotime() function, which parses a strings containing a date/time representation, such as "2004-04-18 17:59 CEST", "April 18, 2004" and the like. With so many different formats one guy in the past crafted a parser for this basing the syntax on GNU tar . The original function had some problems, or was missing some formats (such as the highly useful ISO 8601 formats) and during time this original parser was extended. it might have been a nice and simple bison parser, with a hand craften lexer, but I can assure you that it is now shitty, buggy and totaly unmaintainable. Nobody knows what formats it's supposed to parse either.
With those four problems in my head I decided to redo this shitty old and messy parser by using re2c to do the parsing. Their is a problem though as I don't know which format it's supposed to parse at all (except the GNU tar things and ISO 8601 stuff) so I'm asking you guys which formats it should be able to parse, and which formats you already parse with the strtotime() function.