newxml/chapter06/flex.xml

   1 <?xml version="1.0" encoding="ISO-8859-1"?>
   2 <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
   3   <!ENTITY % general-entities SYSTEM "../general.ent">
   4   %general-entities;
   5 ]>
   6 <sect1 id="ch-system-flex" xreflabel="Flex">
   7 <title>Flex-&flex-version;</title>
   8 <?dbhtml filename="flex.html"?>
   9
  10 <indexterm zone="ch-system-flex"><primary sortas="a-Flex">Flex</primary></indexterm>
  11
  12 <para>The Flex package contains a utility for generating programs that
  13 recognize patterns in text.</para>
  14
  15 <screen>&buildtime; 0.1 SBU
  16 &diskspace; 3.4 MB</screen>
  17
  18 <para>Flex installation depends on: Bash, Binutils, Bison, Coreutils, Diffutils,
  19 GCC, Gettext, Glibc, Grep, M4, Make, Sed.</para>
  20
  21
  22
  23 <sect2>
  24 <title>Installation of Flex</title>
  25
  26 <para>Prepare Flex for compilation:</para>
  27
  28 <screen><userinput>./configure --prefix=/usr</userinput></screen>
  29
  30 <para>Compile the package:</para>
  31
  32 <screen><userinput>make</userinput></screen>
  33
  34 <para>To test the results, issue:
  35 <userinput>make bigcheck</userinput>.</para>
  36
  37 <para>Now install the package:</para>
  38
  39 <screen><userinput>make install</userinput></screen>
  40
  41 <para>There are some packages that expect to find the <emphasis>lex</emphasis>
  42 library in <filename>/usr/lib</filename>. Create a symlink to account for
  43 this:</para>
  44
  45 <screen><userinput>ln -s libfl.a /usr/lib/libl.a</userinput></screen>
  46
  47 <para>A few programs don't know about <command>flex</command> yet and try
  48 to run its predecessor <command>lex</command>. To support those programs,
  49 create a wrapper script named <filename>lex</filename> that calls
  50 <command>flex</command> in <emphasis>lex</emphasis> emulation mode:</para>
  51
  52 <screen><userinput>cat &gt; /usr/bin/lex &lt;&lt; "EOF"</userinput>
  53 #!/bin/sh
  54 # Begin /usr/bin/lex
  55
  56 exec /usr/bin/flex -l "$@"
  57
  58 # End /usr/bin/lex
  59 <userinput>EOF
  60 chmod 755 /usr/bin/lex</userinput></screen>
  61
  62 </sect2>
  63
  64
  65 <sect2 id="contents-flex"><title>Contents of Flex</title>
  66
  67 <para><emphasis>Installed programs</emphasis>: flex, flex++ (link to flex)
  68 and lex</para>
  69
  70 <para><emphasis>Installed library</emphasis>: libfl.a</para>
  71
  72 </sect2>
  73
  74
  75 <sect2><title>Short descriptions</title>
  76
  77 <indexterm zone="ch-system-flex flex"><primary sortas="b-flex">flex</primary></indexterm>
  78 <para id="flex"><command>flex</command> is a tool for generating programs that
  79 recognize patterns in text. Pattern recognition is useful in many applications.
  80 From a set of rules on what to look for, flex makes a program that looks for
  81 those patterns. The reason to use flex is that it is much easier to specify
  82 the rules for a pattern-finding program than to write the program.</para>
  83
  84 <indexterm zone="ch-system-flex flex-"><primary sortas="b-flex++">flex++</primary></indexterm>
  85 <para id="flex-"><command>flex++</command> invokes a version of flex that is used
  86 exclusively for C++ scanners.</para>
  87
  88 <indexterm zone="ch-system-flex libfl.a"><primary sortas="c-libfl.a">libfl.a</primary></indexterm>
  89 <para id="libfl.a"><command>libfl.a</command> is the flex library.</para>
  90
  91 </sect2>
  92
  93
  94
  95 </sect1>