Looking for code to quickly build DFSAs from Reg Exprs

Joseph Edward Hummel <jhummel@esp.ICS.UCI.EDU>
Fri, 4 Dec 1992 07:04:34 GMT

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Looking for code to quickly build DFSAs from Reg Exprs jhummel@esp.ICS.UCI.EDU (Joseph Edward Hummel) (1992-12-04)
Re: Looking for code to quickly build DFSAs from Reg Exprs markh@csd4.csd.uwm.edu (1992-12-05)
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Newsgroups: comp.compilers
From: Joseph Edward Hummel <jhummel@esp.ICS.UCI.EDU>
Organization: Compilers Central
Date: Fri, 4 Dec 1992 07:04:34 GMT
Keywords: DFA, lex, question, comment

Hello. I'm looking for code that builds FSAs from regular expressions.
However, I also need to perform intersection and complementation
of regular expressions, which seems to imply that DFSAs are ultimately
needed. I actually never need to "run" the resulting DFSA, instead
I need to perform e.g. intersections and checks to see if the language
accepted is empty or not. Thus, speed of machine execution is not
important, but speed of construction and operations such as intersection
is crucial. I was ruling out lex/flex, since they build machines designed
to run fast, while I need fast construction of machines whose format is
also easy to manipulate. Any ideas? (Anyone know what kind of machines
the grep/egrep/fgrep family build? Probably not appropriate for the same
reasons as lex).


Thanks in advance for whatever leads you can offer,


    - joe


Joe Hummel
Dept of ICS
UC-Irvine
Irvine, CA 92717
jhummel@ics.uci.edu
[Last time I checked, egrep used a DFA, grep used an NFA, and fgrep used
a hack. -John]
--


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