lib/perl5/5.8.8/Pod/Text/Overstrike.pm

   1 # Pod::Text::Overstrike -- Convert POD data to formatted overstrike text
   2 # $Id: Overstrike.pm,v 1.10 2002/08/04 03:35:01 eagle Exp $
   3 #
   4 # Created by Joe Smith <Joe.Smith@inwap.com> 30-Nov-2000
   5 #   (based on Pod::Text::Color by Russ Allbery <rra@stanford.edu>)
   6 #
   7 # This program is free software; you may redistribute it and/or modify it
   8 # under the same terms as Perl itself.
   9 #
  10 # This was written because the output from:
  11 #
  12 #     pod2text Text.pm > plain.txt; less plain.txt
  13 #
  14 # is not as rich as the output from
  15 #
  16 #     pod2man Text.pm | nroff -man > fancy.txt; less fancy.txt
  17 #
  18 # and because both Pod::Text::Color and Pod::Text::Termcap are not device
  19 # independent.
  20
  21 ##############################################################################
  22 # Modules and declarations
  23 ##############################################################################
  24
  25 package Pod::Text::Overstrike;
  26
  27 require 5.004;
  28
  29 use Pod::Text ();
  30
  31 use strict;
  32 use vars qw(@ISA $VERSION);
  33
  34 @ISA = qw(Pod::Text);
  35
  36 # Don't use the CVS revision as the version, since this module is also in Perl
  37 # core and too many things could munge CVS magic revision strings.  This
  38 # number should ideally be the same as the CVS revision in podlators, however.
  39 $VERSION = 1.10;
  40
  41
  42 ##############################################################################
  43 # Overrides
  44 ##############################################################################
  45
  46 # Make level one headings bold, overridding any existing formatting.
  47 sub cmd_head1 {
  48     my ($self, $text, $line) = @_;
  49     $text =~ s/\s+$//;
  50     $text = $self->strip_format ($self->interpolate ($text, $line));
  51     $text =~ s/(.)/$1\b$1/g;
  52     $self->SUPER::cmd_head1 ($text);
  53 }
  54
  55 # Make level two headings bold, overriding any existing formatting.
  56 sub cmd_head2 {
  57     my ($self, $text, $line) = @_;
  58     $text =~ s/\s+$//;
  59     $text = $self->strip_format ($self->interpolate ($text, $line));
  60     $text =~ s/(.)/$1\b$1/g;
  61     $self->SUPER::cmd_head2 ($text);
  62 }
  63
  64 # Make level three headings underscored, overriding any existing formatting.
  65 sub cmd_head3 {
  66     my ($self, $text, $line) = @_;
  67     $text =~ s/\s+$//;
  68     $text = $self->strip_format ($self->interpolate ($text, $line));
  69     $text =~ s/(.)/_\b$1/g;
  70     $self->SUPER::cmd_head3 ($text);
  71 }
  72
  73 # Level four headings look like level three headings.
  74 sub cmd_head4 {
  75     my ($self, $text, $line) = @_;
  76     $text =~ s/\s+$//;
  77     $text = $self->strip_format ($self->interpolate ($text, $line));
  78     $text =~ s/(.)/_\b$1/g;
  79     $self->SUPER::cmd_head4 ($text);
  80 }
  81
  82 # The common code for handling all headers.  We have to override to avoid
  83 # interpolating twice and because we don't want to honor alt.
  84 sub heading {
  85     my ($self, $text, $line, $indent, $marker) = @_;
  86     $self->item ("\n\n") if defined $$self{ITEM};
  87     $text .= "\n" if $$self{loose};
  88     my $margin = ' ' x ($$self{margin} + $indent);
  89     $self->output ($margin . $text . "\n");
  90 }
  91
  92 # Fix the various formatting codes.
  93 sub seq_b { local $_ = strip_format (@_); s/(.)/$1\b$1/g; $_ }
  94 sub seq_f { local $_ = strip_format (@_); s/(.)/_\b$1/g; $_ }
  95 sub seq_i { local $_ = strip_format (@_); s/(.)/_\b$1/g; $_ }
  96
  97 # Output any included code in bold.
  98 sub output_code {
  99     my ($self, $code) = @_;
 100     $code =~ s/(.)/$1\b$1/g;
 101     $self->output ($code);
 102 }
 103
 104 # We unfortunately have to override the wrapping code here, since the normal
 105 # wrapping code gets really confused by all the backspaces.
 106 sub wrap {
 107     my $self = shift;
 108     local $_ = shift;
 109     my $output = '';
 110     my $spaces = ' ' x $$self{MARGIN};
 111     my $width = $$self{width} - $$self{MARGIN};
 112     while (length > $width) {
 113         # This regex represents a single character, that's possibly underlined
 114         # or in bold (in which case, it's three characters; the character, a
 115         # backspace, and a character).  Use [^\n] rather than . to protect
 116         # against odd settings of $*.
 117         my $char = '(?:[^\n][\b])?[^\n]';
 118         if (s/^((?>$char){0,$width})(?:\Z|\s+)//) {
 119             $output .= $spaces . $1 . "\n";
 120         } else {
 121             last;
 122         }
 123     }
 124     $output .= $spaces . $_;
 125     $output =~ s/\s+$/\n\n/;
 126     $output;
 127 }
 128
 129 ##############################################################################
 130 # Utility functions
 131 ##############################################################################
 132
 133 # Strip all of the formatting from a provided string, returning the stripped
 134 # version.
 135 sub strip_format {
 136     my ($self, $text) = @_;
 137     $text =~ s/(.)[\b]\1/$1/g;
 138     $text =~ s/_[\b]//g;
 139     return $text;
 140 }
 141
 142 ##############################################################################
 143 # Module return value and documentation
 144 ##############################################################################
 145
 146 1;
 147 __END__
 148
 149 =head1 NAME
 150
 151 Pod::Text::Overstrike - Convert POD data to formatted overstrike text
 152
 153 =head1 SYNOPSIS
 154
 155     use Pod::Text::Overstrike;
 156     my $parser = Pod::Text::Overstrike->new (sentence => 0, width => 78);
 157
 158     # Read POD from STDIN and write to STDOUT.
 159     $parser->parse_from_filehandle;
 160
 161     # Read POD from file.pod and write to file.txt.
 162     $parser->parse_from_file ('file.pod', 'file.txt');
 163
 164 =head1 DESCRIPTION
 165
 166 Pod::Text::Overstrike is a simple subclass of Pod::Text that highlights
 167 output text using overstrike sequences, in a manner similar to nroff.
 168 Characters in bold text are overstruck (character, backspace, character) and
 169 characters in underlined text are converted to overstruck underscores
 170 (underscore, backspace, character).  This format was originally designed for
 171 hardcopy terminals and/or lineprinters, yet is readable on softcopy (CRT)
 172 terminals.
 173
 174 Overstruck text is best viewed by page-at-a-time programs that take
 175 advantage of the terminal's B<stand-out> and I<underline> capabilities, such
 176 as the less program on Unix.
 177
 178 Apart from the overstrike, it in all ways functions like Pod::Text.  See
 179 L<Pod::Text> for details and available options.
 180
 181 =head1 BUGS
 182
 183 Currently, the outermost formatting instruction wins, so for example
 184 underlined text inside a region of bold text is displayed as simply bold.
 185 There may be some better approach possible.
 186
 187 =head1 SEE ALSO
 188
 189 L<Pod::Text>, L<Pod::Parser>
 190
 191 The current version of this module is always available from its web site at
 192 L<http://www.eyrie.org/~eagle/software/podlators/>.  It is also part of the
 193 Perl core distribution as of 5.6.0.
 194
 195 =head1 AUTHOR
 196
 197 Joe Smith <Joe.Smith@inwap.com>, using the framework created by Russ Allbery
 198 <rra@stanford.edu>.
 199
 200 =head1 COPYRIGHT AND LICENSE
 201
 202 Copyright 2000 by Joe Smith <Joe.Smith@inwap.com>.
 203 Copyright 2001 by Russ Allbery <rra@stanford.edu>.
 204
 205 This program is free software; you may redistribute it and/or modify it
 206 under the same terms as Perl itself.
 207
 208 =cut