Flex - a scanner generator - Overview

Overview

This manual describes flex , a tool for generating programs that perform pattern-matching on text. The manual includes both tutorial and reference sections:

Description

a brief overview of the tool

Some Simple Examples

Format Of The Input File

Patterns

the extended regular expressions used by flex

How The Input Is Matched

the rules for determining what has been matched

Actions

how to specify what to do when a pattern is matched

The Generated Scanner

details regarding the scanner that flex produces; how to control the input source

Start Conditions

introducing context into your scanners, and managing "mini-scanners"

Multiple Input Buffers

how to manipulate multiple input sources; how to scan from strings instead of files

End-of-file Rules

special rules for matching the end of the input

Miscellaneous Macros

a summary of macros available to the actions

Values Available To The User

a summary of values available to the actions

Interfacing With Yacc

connecting flex scanners together with yacc parsers

Options

flex command-line options, and the "%option" directive

Performance Considerations

how to make your scanner go as fast as possible

Generating C++ Scanners

the (experimental) facility for generating C++ scanner classes

Incompatibilities With Lex And POSIX

how flex differs from AT&T lex and the POSIX lex standard

Diagnostics

those error messages produced by flex (or scanners it generates) whose meanings might not be apparent

Files

files used by flex

Deficiencies / Bugs

known problems with flex

See Also

other documentation, related tools

Author

includes contact information