lib/perl5/5.6.1/Text/Tabs.pm

   1
   2 package Text::Tabs;
   3
   4 require Exporter;
   5
   6 @ISA = (Exporter);
   7 @EXPORT = qw(expand unexpand $tabstop);
   8
   9 use vars qw($VERSION $tabstop $debug);
  10 $VERSION = 98.112801;
  11
  12 use strict;
  13
  14 BEGIN   {
  15         $tabstop = 8;
  16         $debug = 0;
  17 }
  18
  19 sub expand
  20 {
  21         my (@l) = @_;
  22         for $_ (@l) {
  23                 1 while s/(^|\n)([^\t\n]*)(\t+)/
  24                         $1. $2 . (" " x
  25                                 ($tabstop * length($3)
  26                                 - (length($2) % $tabstop)))
  27                         /sex;
  28         }
  29         return @l if wantarray;
  30         return $l[0];
  31 }
  32
  33 sub unexpand
  34 {
  35         my (@l) = @_;
  36         my @e;
  37         my $x;
  38         my $line;
  39         my @lines;
  40         my $lastbit;
  41         for $x (@l) {
  42                 @lines = split("\n", $x, -1);
  43                 for $line (@lines) {
  44                         $line = expand($line);
  45                         @e = split(/(.{$tabstop})/,$line,-1);
  46                         $lastbit = pop(@e);
  47                         $lastbit = '' unless defined $lastbit;
  48                         $lastbit = "\t"
  49                                 if $lastbit eq " "x$tabstop;
  50                         for $_ (@e) {
  51                                 if ($debug) {
  52                                         my $x = $_;
  53                                         $x =~ s/\t/^I\t/gs;
  54                                         print "sub on '$x'\n";
  55                                 }
  56                                 s/  +$/\t/;
  57                         }
  58                         $line = join('',@e, $lastbit);
  59                 }
  60                 $x = join("\n", @lines);
  61         }
  62         return @l if wantarray;
  63         return $l[0];
  64 }
  65
  66 1;
  67 __END__
  68
  69
  70 =head1 NAME
  71
  72 Text::Tabs -- expand and unexpand tabs per the unix expand(1) and unexpand(1)
  73
  74 =head1 SYNOPSIS
  75
  76 use Text::Tabs;
  77
  78 $tabstop = 4;
  79 @lines_without_tabs = expand(@lines_with_tabs);
  80 @lines_with_tabs = unexpand(@lines_without_tabs);
  81
  82 =head1 DESCRIPTION
  83
  84 Text::Tabs does about what the unix utilities expand(1) and unexpand(1)
  85 do.  Given a line with tabs in it, expand will replace the tabs with
  86 the appropriate number of spaces.  Given a line with or without tabs in
  87 it, unexpand will add tabs when it can save bytes by doing so.  Invisible
  88 compression with plain ascii!
  89
  90 =head1 BUGS
  91
  92 expand doesn't handle newlines very quickly -- do not feed it an
  93 entire document in one string.  Instead feed it an array of lines.
  94
  95 =head1 AUTHOR
  96
  97 David Muir Sharnoff <muir@idiom.com>