[ragel-users] Parsing date strings

ragel-user at jgoettgens.de ragel-user at jgoettgens.de
Thu Aug 11 14:15:32 UTC 2011

Hi Luis,

my Maya colleague next door  believes that "-3456781203" refers to a date in 
December instead of May. Could he be right?

Given the fixed format of your date strings, the question is not really 
whether you can scan it with Ragel (or flex, or what else), but whether such 
a tool is the right tool to do that.  Somehow you always need to extract the 
last 2+2 chars and validate them, but this essentially makes you going 
backwards in your machine (or using further memory) which is not within the 
realm of a "pure" FSM (http://en.wikipedia.org/wiki/Finite_state_machine). 
However, Ragel allows you to easily add the necessary "counting".

It depends on how you get your date strings whether using Ragel is benficial 
or not. If you have just isolated strings (i.e. the entire string, so you 
know where it ends) it probably doesn't. If you need to extract the date 
from a stream of other tokens that can easily described by a FSM, then it 


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