package Text::Tabs; require Exporter; @ISA = (Exporter); @EXPORT = qw(expand unexpand $tabstop); use vars qw($VERSION $tabstop $debug); $VERSION = 2009.0305; use strict; BEGIN { $tabstop = 8; $debug = 0; } sub expand { my @l; my $pad; for ( @_ ) { my $s = ''; for (split(/^/m, $_, -1)) { my $offs = 0; s{\t}{ $pad = $tabstop - (pos() + $offs) % $tabstop; $offs += $pad - 1; " " x $pad; }eg; $s .= $_; } push(@l, $s); } return @l if wantarray; return $l[0]; } sub unexpand { my (@l) = @_; my @e; my $x; my $line; my @lines; my $lastbit; my $ts_as_space = " "x$tabstop; for $x (@l) { @lines = split("\n", $x, -1); for $line (@lines) { $line = expand($line); @e = split(/(.{$tabstop})/,$line,-1); $lastbit = pop(@e); $lastbit = '' unless defined $lastbit; $lastbit = "\t" if $lastbit eq $ts_as_space; for $_ (@e) { if ($debug) { my $x = $_; $x =~ s/\t/^I\t/gs; print "sub on '$x'\n"; } s/ +$/\t/; } $line = join('',@e, $lastbit); } $x = join("\n", @lines); } return @l if wantarray; return $l[0]; } 1; __END__ sub expand { my (@l) = @_; for $_ (@l) { 1 while s/(^|\n)([^\t\n]*)(\t+)/ $1. $2 . (" " x ($tabstop * length($3) - (length($2) % $tabstop))) /sex; } return @l if wantarray; return $l[0]; } =head1 NAME Text::Tabs -- expand and unexpand tabs per the unix expand(1) and unexpand(1) =head1 SYNOPSIS use Text::Tabs; $tabstop = 4; # default = 8 @lines_without_tabs = expand(@lines_with_tabs); @lines_with_tabs = unexpand(@lines_without_tabs); =head1 DESCRIPTION Text::Tabs does about what the unix utilities expand(1) and unexpand(1) do. Given a line with tabs in it, expand will replace the tabs with the appropriate number of spaces. Given a line with or without tabs in it, unexpand will add tabs when it can save bytes by doing so (just like C). Invisible compression with plain ASCII! =head1 EXAMPLE #!perl # unexpand -a use Text::Tabs; while (<>) { print unexpand $_; } Instead of the C comand, use: perl -MText::Tabs -n -e 'print expand $_' Instead of the C command, use: perl -MText::Tabs -n -e 'print unexpand $_' =head1 LICENSE Copyright (C) 1996-2002,2005,2006 David Muir Sharnoff. Copyright (C) 2005 Aristotle Pagaltzis This module may be modified, used, copied, and redistributed at your own risk. Publicly redistributed modified versions must use a different name.