src/HOL/Lex/README.html
author paulson
Tue, 16 Jul 1996 15:49:46 +0200
changeset 1868 836950047d85
parent 1345 d4e26f632bca
child 3279 815ef5848324
permissions -rw-r--r--
Put in minimal simpset to avoid excessive simplification, just as in revision 1.9 of HOL/indrule.ML

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<H1>A Simplified Scanner Generator</H1>

This is half of a simplified functional scanner generator. The overall design
is like this:
<PRE>
         regular expression
                  |
                  v
             -----------
             | mk_auto |
             -----------
                  |
        deterministic automaton
                  |
                  v
           ----------------
string --> | auto_chopper | --> chopped up string
           ----------------
</PRE>
A chopped up string is a pair of
<UL>
<LI>a prefix of the input string, chopped up into words of the language,
<LI>together with the remaining suffix.
</UL>
For example, if the language consists just of the word <KBD>ab</KBD>, the
input <KBD>ababaab</KBD> is partitioned into a chopped up prefix
<KBD>[ab,ab]</KBD> and the suffix <KBD>aab</KBD>.
<P>

The auto_chopper is implemented in theory AutoChopper. The top part of the
diagram, i.e. the translation of regular expressions into deterministic
finite automata is still missing.  <P>

<H2>M.Sc./Diplom/Fopra Project</H2>

Task: formalize the translation of regular expressions into deterministic
finite automata. We are looking for a theoretically inclined student who
likes automata theory and is not afraid of logic and proofs.  Sounds
interesting? Then contact <A
HREF="http://www4.informatik.tu-muenchen.de/~nipkow/">Tobias Nipkow</A> or <A
HREF="http://www4.informatik.tu-muenchen.de/~pusch/">Cornelia Pusch</A>.
This project is also suitable as a joint "Fopra" for two students.

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