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Flex (Faster Lex) Help Pages |
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Flex (Fast Lex) is a tool for generating scanners: programs which recognized lexical patterns in text. Flex reads the given input files, or its standard input if no file names are given, for a description of a scanner to generate. The description is in the form of pairs of regular expressions and C code, called rules.
flex generates as output a C source file, lex.yy.c, which defines a routine yylex( ).
This file is compiled and linked with the -lfl library to produce an executable.
When the executable is run, it analyzes its input for occurrences of the regular expressions.
Whenever it finds one, it executes the corresponding C code.
man flex