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[REBOL] Re: Parse versus Regular Expressions

From: g:santilli:tiscalinet:it at: 5-Apr-2003 22:00

Hi Joel, On Saturday, April 5, 2003, 5:00:08 PM, you wrote: JN> /(.+)\1+$/ I wonder what is the RE parser doing under the hood. What is the complexity of such a innocent-looking RE? JN> I'm really interested in how a PARSE expert would approach the same JN> task. Any takers? Well, I wouldn't use PARSE probably. I would do it this way: for all the divisors of the length of the input string, check to see if the string is made of a repetition of a substring that has the length of the divisor. If no solution is found, apply the same test starting at the next position of the string, recursively. Regards, Gabriele. -- Gabriele Santilli <[g--santilli--tiscalinet--it]> -- REBOL Programmer Amigan -- AGI L'Aquila -- REB: