lib/perl5/5.6.1/Text/Wrap.pm

   1 package Text::Wrap;
   2
   3 require Exporter;
   4
   5 @ISA = qw(Exporter);
   6 @EXPORT = qw(wrap fill);
   7 @EXPORT_OK = qw($columns $break $huge);
   8
   9 $VERSION = 2001.0131;
  10
  11 use vars qw($VERSION $columns $debug $break $huge);
  12 use strict;
  13
  14 BEGIN   {
  15         $columns = 76;  # <= screen width
  16         $debug = 0;
  17         $break = '\s';
  18         $huge = 'wrap'; # alternatively: 'die' or 'overflow'
  19 }
  20
  21 use Text::Tabs qw(expand unexpand);
  22
  23 sub wrap
  24 {
  25         my ($ip, $xp, @t) = @_;
  26
  27         my $r = "";
  28         my $tail = pop(@t);
  29         my $t = expand(join("", (map { /\s+\Z/ ? ( $_ ) : ($_, ' ') } @t), $tail));
  30         my $lead = $ip;
  31         my $ll = $columns - length(expand($ip)) - 1;
  32         my $nll = $columns - length(expand($xp)) - 1;
  33         my $nl = "";
  34         my $remainder = "";
  35
  36         pos($t) = 0;
  37         while ($t !~ /\G\s*\Z/gc) {
  38                 if ($t =~ /\G([^\n]{0,$ll})($break|\Z(?!\n))/xmgc) {
  39                         $r .= unexpand($nl . $lead . $1);
  40                         $remainder = $2;
  41                 } elsif ($huge eq 'wrap' && $t =~ /\G([^\n]{$ll})/gc) {
  42                         $r .= unexpand($nl . $lead . $1);
  43                         $remainder = "\n";
  44                 } elsif ($huge eq 'overflow' && $t =~ /\G([^\n]*?)($break|\Z(?!\n))/xmgc) {
  45                         $r .= unexpand($nl . $lead . $1);
  46                         $remainder = $2;
  47                 } elsif ($huge eq 'die') {
  48                         die "couldn't wrap '$t'";
  49                 } else {
  50                         die "This shouldn't happen";
  51                 }
  52
  53                 $lead = $xp;
  54                 $ll = $nll;
  55                 $nl = "\n";
  56         }
  57         $r .= $remainder;
  58
  59         print "-----------$r---------\n" if $debug;
  60
  61         print "Finish up with '$lead'\n" if $debug;
  62
  63         $r .= $lead . substr($t, pos($t), length($t)-pos($t))
  64                 if pos($t) ne length($t);
  65
  66         print "-----------$r---------\n" if $debug;;
  67
  68         return $r;
  69 }
  70
  71 sub fill
  72 {
  73         my ($ip, $xp, @raw) = @_;
  74         my @para;
  75         my $pp;
  76
  77         for $pp (split(/\n\s+/, join("\n",@raw))) {
  78                 $pp =~ s/\s+/ /g;
  79                 my $x = wrap($ip, $xp, $pp);
  80                 push(@para, $x);
  81         }
  82
  83         # if paragraph_indent is the same as line_indent,
  84         # separate paragraphs with blank lines
  85
  86         my $ps = ($ip eq $xp) ? "\n\n" : "\n";
  87         return join ($ps, @para);
  88 }
  89
  90 1;
  91 __END__
  92
  93 =head1 NAME
  94
  95 Text::Wrap - line wrapping to form simple paragraphs
  96
  97 =head1 SYNOPSIS
  98
  99 B<Example 1>
 100
 101         use Text::Wrap
 102
 103         $initial_tab = "\t";    # Tab before first line
 104         $subsequent_tab = "";   # All other lines flush left
 105
 106         print wrap($initial_tab, $subsequent_tab, @text);
 107         print fill($initial_tab, $subsequent_tab, @text);
 108
 109         @lines = wrap($initial_tab, $subsequent_tab, @text);
 110
 111         @paragraphs = fill($initial_tab, $subsequent_tab, @text);
 112
 113 B<Example 2>
 114
 115         use Text::Wrap qw(wrap $columns $huge);
 116
 117         $columns = 132;         # Wrap at 132 characters
 118         $huge = 'die';
 119         $huge = 'wrap';
 120         $huge = 'overflow';
 121
 122 B<Example 3>
 123
 124         use Text::Wrap
 125
 126         $Text::Wrap::columns = 72;
 127         print wrap('', '', @text);
 128
 129 =head1 DESCRIPTION
 130
 131 Text::Wrap::wrap() is a very simple paragraph formatter.  It formats a
 132 single paragraph at a time by breaking lines at word boundries.
 133 Indentation is controlled for the first line (C<$initial_tab>) and
 134 all subsquent lines (C<$subsequent_tab>) independently.  Please note:
 135 C<$initial_tab> and C<$subsequent_tab> are the literal strings that will
 136 be used: it is unlikley you would want to pass in a number.
 137
 138 Lines are wrapped at C<$Text::Wrap::columns> columns.  C<$Text::Wrap::columns>
 139 should be set to the full width of your output device.  In fact,
 140 every resulting line will have length of no more than C<$columns - 1>.
 141
 142 Beginner note: In example 2, above C<$columns> is imported into
 143 the local namespace, and set locally.  In example 3,
 144 C<$Text::Wrap::columns> is set in its own namespace without importing it.
 145
 146 When words that are longer than C<$columns> are encountered, they
 147 are broken up.  C<wrap()> adds a C<"\n"> at column C<$columns>.
 148 This behavior can be overridden by setting C<$huge> to
 149 'die' or to 'overflow'.  When set to 'die', large words will cause
 150 C<die()> to be called.  When set to 'overflow', large words will be
 151 left intact.
 152
 153 Text::Wrap::fill() is a simple multi-paragraph formatter.  It formats
 154 each paragraph separately and then joins them together when it's done.  It
 155 will destory any whitespace in the original text.  It breaks text into
 156 paragraphs by looking for whitespace after a newline.  In other respects
 157 it acts like wrap().
 158
 159 When called in list context, C<wrap()> will return a list of lines and
 160 C<fill()> will return a list of paragraphs.
 161
 162 Historical notes: Older versions of C<wrap()> and C<fill()> always
 163 returned strings.  Also, 'die' used to be the default value of
 164 C<$huge>.  Now, 'wrap' is the default value.
 165
 166 =head1 EXAMPLE
 167
 168         print wrap("\t","","This is a bit of text that forms
 169                 a normal book-style paragraph");
 170
 171 =head1 AUTHOR
 172
 173 David Muir Sharnoff <muir@idiom.com> with help from Tim Pierce and
 174 many many others.
 175