Unformatted text preview: Both the above formalisms lead to algorithms for constructing acceptors, or lexical analyzers, provided that we have well-defined tokens, for example with RegExs. One of such algorithms is due to Thompson [and also McNathon and Yamada] (see Section 3.7.4) Instance: a regular expression r Question: what is a NFA M that accepts L(r)? (i.e., L(r) = M(r)) Examples:-------Regular definition for numbers (see our textbook). Regular expression for dates (such as Sep 2, 2010, 2010-09-02, 09/02/2010) Regular expression for well-formed e-mail addresses (defined in RFC 5322). Finite automata for various sets of binary numbers. Assignments:---------See the class Web-page for hw2 and for practice (not hw) pertaining to RegEx, Thompson's construction. Similarly, see the course Web-page for a programming assignment....
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This document was uploaded on 12/14/2010.
- Fall '09