lfs/chapter06/flex.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../general.ent">
  %general-entities;
]>

<sect1 id="ch-system-flex" role="wrap">
  <?dbhtml filename="flex.html"?>

  <sect1info condition="script">
    <productname>flex</productname>
    <productnumber>&flex-version;</productnumber>
    <address>&flex-url;</address>
  </sect1info>

  <title>Flex-&flex-version;</title>

  <indexterm zone="ch-system-flex">
    <primary sortas="a-Flex">Flex</primary>
  </indexterm>

  <sect2 role="package">
    <title/>

    <para>The Flex package contains a utility for generating programs that
    recognize patterns in text.</para>

    <segmentedlist>
      <segtitle>&buildtime;</segtitle>
      <segtitle>&diskspace;</segtitle>

      <seglistitem>
        <seg>&flex-ch6-sbu;</seg>
        <seg>&flex-ch6-du;</seg>
      </seglistitem>
    </segmentedlist>

  </sect2>

  <sect2 role="installation">
    <title>Installation of Flex</title>

    <para>Apply a patch that fixes a bug in the C++ scanner generator, that causes scanner compilation to fail when using GCC-&gcc-version;:</para>

<screen><userinput remap="pre">patch -Np1 -i ../&flex-gcc-patch;</userinput></screen>

    <para>Prepare Flex for compilation:</para>

<screen><userinput remap="configure">./configure --prefix=/usr</userinput></screen>

    <para>Compile the package:</para>

<screen><userinput remap="make">make</userinput></screen>

    <para>To test the results (about 0.5 SBU), issue:</para>

<screen><userinput remap="test">make check</userinput></screen>

    <para>Install the package:</para>

<screen><userinput remap="install">make install</userinput></screen>

    <para>There are some packages that expect to find the
    <filename class="libraryfile">lex</filename> library in <filename
    class="directory">/usr/lib</filename>. Create a symlink to account for
    this:</para>

<screen><userinput remap="install">ln -sv libfl.a /usr/lib/libl.a</userinput></screen>

    <para>A few programs do not know about <command>flex</command> yet and
    try to run its predecessor, <command>lex</command>. To support those
    programs, create a wrapper script named <filename>lex</filename> that
    calls <filename>flex</filename> in <command>lex</command> emulation
    mode:</para>

<screen><userinput remap="install">cat &gt; /usr/bin/lex &lt;&lt; "EOF"
<literal>#!/bin/sh
# Begin /usr/bin/lex

exec /usr/bin/flex -l "$@"

# End /usr/bin/lex</literal>
EOF
chmod -v 755 /usr/bin/lex</userinput></screen>

    <para>If desired, install the <filename>flex.pdf</filename> documentation
    file:</para>

<screen><userinput remap="install">mkdir -v /usr/share/doc/flex-&flex-version;
cp    -v doc/flex.pdf \
         /usr/share/doc/flex-&flex-version;</userinput></screen>

  </sect2>

  <sect2 id="contents-flex" role="content">
    <title>Contents of Flex</title>

    <segmentedlist>
      <segtitle>Installed programs</segtitle>
      <segtitle>Installed libraries</segtitle>

      <seglistitem>
        <seg>flex and lex</seg>
        <seg>libfl.a and libfl_pic.a</seg>
      </seglistitem>
    </segmentedlist>

    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>

      <varlistentry id="flex">
        <term><command>flex</command></term>
        <listitem>
          <para>A tool for generating programs that recognize patterns in text;
          it allows for the versatility to specify the rules for pattern-finding,
          eradicating the need to develop a specialized program</para>
          <indexterm zone="ch-system-flex flex">
            <primary sortas="b-flex">flex</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="lex">
        <term><command>lex</command></term>
        <listitem>
          <para>A script that runs <command>flex</command> in
          <command>lex</command> emulation mode</para>
          <indexterm zone="ch-system-flex lex">
            <primary sortas="b-lex">lex</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="libfl.a">
        <term><filename class="libraryfile">libfl.a</filename></term>
        <listitem>
          <para>The <filename class="libraryfile">flex</filename> library</para>
          <indexterm zone="ch-system-flex libfl.a">
            <primary sortas="c-libfl.a">libfl.a</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>