Flex (GNU)

See also: Flex (homonymy)

Flex is the implementation GNU of the lexical Analyseur Lex. One generally associates it with the syntactic Analyze Bison which is the implementation GNU of Yacc.

Flex is a tool to generate scanners (programs which recognize lexical reasons in text). It reads the input files given, or its standard entry if no file is given, to obtain the description of the scanner to be generated. Description is a list of pairs of rational expressions and code C, called rules. At exit, flex generates a source file in Langage C, called “lex.yy.c', which defines a routine “yylex ()”. This file is compiled and linké (linkage editing) with the option “- lfl” (corresponding to the bookseller flex) in order to produce a workable program. When the achievable one is launched, it analyzes its entry in order to find there occurrences corresponding to the preceding regular expressions. With each found expression, it carries out the code C corresponding…

A similar tool functioning around the language C++ is flex++.

External bonds

official Page

Manual

GNU Flex on the site of project GNU.

Manual

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