CPSC 1280 Lecture Notes - Lecture 20: Nondeterministic Finite Automaton, Stephen Cole Kleene, Theoretical Computer Science
13 Nov 2016
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Document Summary
Road map: introduction to regular expression, basic regular expressions, extended regular expressions. Regular expression: a regular expression (regexor regexpfor short) is a sequence of characters that define a search pattern, similar to wild cards, more precise, more complicated, terms. Character: basic unit of text, letter, number, punctuation, space, etc. String: a sequence of 0 to many characters. Jit compilation: many variations in unix programs at bell labs in the 1970s, including vi, emacs, lex, sed, awk and expr, standardized in posix. 2 in 1992, today regular expressions are widely supported in, programming languages, text processing programs (particular lexers, advanced text editors. The character class: single character matching, specify a group of characters enclosed within a pair of rectangular brackets [ ] Ex: [od] matches either o or d, [od][de]matches four patterns, od, oe, dd, de, to match woodhouse and wodehouse, wo[od][de]house.
