|Regular expressions & finite automata. email@example.com (Mike Harrison) (1990-08-15)|
|Regular expressions & finite automata. firstname.lastname@example.org (1990-08-23)|
|Re: Regular expressions & finite automata. email@example.com (1990-08-24)|
|From:||Mike Harrison <firstname.lastname@example.org>|
|Date:||Wed, 15 Aug 90 14:42:31 GMT|
In response to tfd!kent@uunet.UU.NET (Kent Hauser), John wrote:
[Given the well-known equivalence between regular expressions and finite
state machines (albeit not a one-to-one equivalence) there are many programs
that compile regular expressions into FSMs and then run them.
In my copy of Aho & Ullman - 'The theory of parsing translation and
compiling', regular sets are shown to be equivalent to:
- regular expressions,
- right linear grammars,
- finite automata.
Thus, I don't quite understand the "albeit not a one-to-one
Incidentally, this book is an excellent reference for a rigorous treatment of
many aspects of language theory.
Michael P. Harrison - Software Group - Inmos Ltd. UK.
UK : email@example.com, US : firstname.lastname@example.org
[There are many equivalent DFAs that a regular expression can translate to,
and vice versa. After all, any regular expression can be written in
infinitely many equivalent ways, e.g. a(b|c) vs. ab|ac, or to be really
pedantic, x vs. (x|x) vs. (x|x|x) ... -John]
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