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ocaml / man / ocamllex.m

.\"***********************************************************************
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.\"*                                OCaml                                *
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.\"*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *
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.\"*  Copyright 1996 Institut National de Recherche en Informatique et   *
.\"*  en Automatique.  All rights reserved.  This file is distributed    *
.\"*  under the terms of the Q Public License version 1.0.               *
.\"*                                                                     *
.\"***********************************************************************
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.\" $Id$
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.TH OCAMLLEX 1

.SH NAME
ocamllex \- The OCaml lexer generator

.SH SYNOPSIS
.B ocamllex
[
.BI \-o \ output-file
]
[
.B \-ml
]
.I filename.mll

.SH DESCRIPTION

The
.BR ocamllex (1)
command generates OCaml lexers from a set of regular
expressions with associated semantic actions, in the style of
.BR lex (1).

Running
.BR ocamllex (1)
on the input file
.IR lexer \&.mll
produces OCaml code for a lexical analyzer in file
.IR lexer \&.ml.

This file defines one lexing function per entry point in the lexer
definition. These functions have the same names as the entry
points. Lexing functions take as argument a lexer buffer, and return
the semantic attribute of the corresponding entry point.

Lexer buffers are an abstract data type implemented in the standard
library module Lexing. The functions Lexing.from_channel,
Lexing.from_string and Lexing.from_function create
lexer buffers that read from an input channel, a character string, or
any reading function, respectively.

When used in conjunction with a parser generated by
.BR ocamlyacc (1),
the semantic actions compute a value belonging to the type token defined
by the generated parsing module.

.SH OPTIONS

The
.BR ocamllex (1)
command recognizes the following options:
.TP
.B \-ml
Output code that does not use OCaml's built-in automata
interpreter. Instead, the automaton is encoded by OCaml functions.
This option is mainly useful for debugging
.BR ocamllex (1),
using it for production lexers is not recommended.
.TP
.BI \-o \ output\-file
Specify the name of the output file produced by
.BR ocamllex (1).
The default is the input file name, with its extension replaced by .ml.
.TP
.B \-q
Quiet mode.
.BR ocamllex (1)
normally outputs informational messages
to standard output.  They are suppressed if option
.B \-q
is used.
.TP
.BR \-v \ or \ \-version
Print version string and exit.
.TP
.B \-vnum
Print short version number and exit.
.TP
.BR \-help \ or \ \-\-help
Display a short usage summary and exit.

.SH SEE ALSO
.BR ocamlyacc (1).
.br
.IR "The OCaml user's manual" ,
chapter "Lexer and parser generators".