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git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@3860 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
125 lines
4.1 KiB
XML
125 lines
4.1 KiB
XML
<?xml version="1.0" encoding="ISO-8859-1"?>
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<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
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<!ENTITY % general-entities SYSTEM "../general.ent">
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%general-entities;
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]>
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<sect1 id="ch-system-flex" xreflabel="Flex" role="wrap">
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<title>Flex-&flex-version;</title>
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<?dbhtml filename="flex.html"?>
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<indexterm zone="ch-system-flex"><primary sortas="a-Flex">Flex</primary></indexterm>
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<sect2 role="package"><title/>
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<para>The Flex package contains a utility for generating programs that
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recognize patterns in text.</para>
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<segmentedlist>
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<segtitle>&buildtime;</segtitle>
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<segtitle>&diskspace;</segtitle>
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<seglistitem><seg>0.1 SBU</seg><seg>3.4 MB</seg></seglistitem>
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</segmentedlist>
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<segmentedlist>
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<segtitle>Flex installation depends on</segtitle>
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<seglistitem><seg>Bash, Binutils, Bison, Coreutils, Diffutils,
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GCC, Gettext, Glibc, Grep, M4, Make, Sed</seg></seglistitem>
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</segmentedlist>
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</sect2>
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<sect2 role="installation">
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<title>Installation of Flex</title>
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<para>Flex contains several known bugs. Fix these with the following patch:</para>
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<screen><userinput>patch -Np1 -i ../flex-&flex-version;-debian_fixes-2.patch</userinput></screen>
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<para>The GNU autotools detects that the Flex source code has been modified by
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the previous patch, and tries to update the manual page accordingly, but this
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breaks on many systems, and the default page is fine, so make sure it doesn't
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get regenerated:</para>
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<screen><userinput>touch doc/flex.1</userinput></screen>
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<para>Now prepare Flex for compilation:</para>
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<screen><userinput>./configure --prefix=/usr</userinput></screen>
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<para>Compile the package:</para>
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<screen><userinput>make</userinput></screen>
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<para>To test the results, issue:
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<userinput>make check</userinput>.</para>
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<para>Now install the package:</para>
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<screen><userinput>make install</userinput></screen>
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<para>There are some packages that expect to find the <emphasis>lex</emphasis>
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library in <filename>/usr/lib</filename>. Create a symlink to account for
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this:</para>
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<screen><userinput>ln -s libfl.a /usr/lib/libl.a</userinput></screen>
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<para>A few programs don't know about <command>flex</command> yet and try
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to run its predecessor <command>lex</command>. To support those programs,
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create a wrapper script named <filename>lex</filename> that calls
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<command>flex</command> in <emphasis>lex</emphasis> emulation mode:</para>
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<screen><userinput>cat > /usr/bin/lex << "EOF"</userinput>
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#!/bin/sh
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# Begin /usr/bin/lex
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exec /usr/bin/flex -l "$@"
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# End /usr/bin/lex
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<userinput>EOF
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chmod 755 /usr/bin/lex</userinput></screen>
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</sect2>
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<sect2 id="contents-flex" role="content"><title>Contents of Flex</title>
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<segmentedlist>
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<segtitle>Installed programs</segtitle>
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<segtitle>Installed library</segtitle>
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<seglistitem><seg>flex, flex++ (link to flex) and lex</seg>
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<seg>libfl.a</seg></seglistitem>
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</segmentedlist>
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<variablelist><title>Short descriptions</title>
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<varlistentry id="flex">
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<term><command>flex</command></term>
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<listitem>
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<indexterm zone="ch-system-flex flex"><primary sortas="b-flex">flex</primary></indexterm>
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<para>is a tool for generating programs that
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recognize patterns in text. Pattern recognition is useful in many applications.
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From a set of rules on what to look for, <command>flex</command> makes a program that looks for
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those patterns. The reason to use <command>flex</command> is that it is much easier to specify
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the rules for a pattern-finding program than to write the program.</para>
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</listitem>
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</varlistentry>
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<varlistentry id="flex-">
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<term><command>flex++</command></term>
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<listitem>
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<indexterm zone="ch-system-flex flex-"><primary sortas="b-flex++">flex++</primary></indexterm>
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<para>invokes a version of <command>flex</command> that is used exclusively for C++ scanners.</para>
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</listitem>
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</varlistentry>
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<varlistentry id="libfl.a">
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<term><filename class="libraryfile">libfl.a</filename></term>
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<listitem>
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<indexterm zone="ch-system-flex libfl.a"><primary sortas="c-libfl.a">libfl.a</primary></indexterm>
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<para>is the flex library.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</sect2>
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</sect1>
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