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+
+package Text::Tabs;
+
+require Exporter;
+
+@ISA = (Exporter);
+@EXPORT = qw(expand unexpand $tabstop);
+
+use vars qw($VERSION $tabstop $debug);
+$VERSION = 98.112801;
+
+use strict;
+
+BEGIN {
+ $tabstop = 8;
+ $debug = 0;
+}
+
+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];
+}
+
+sub unexpand
+{
+ my (@l) = @_;
+ my @e;
+ my $x;
+ my $line;
+ my @lines;
+ my $lastbit;
+ 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 $lastbit eq " "x$tabstop;
+ 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__
+
+
+=head1 NAME
+
+Text::Tabs -- expand and unexpand tabs per the unix expand(1) and unexpand(1)
+
+=head1 SYNOPSIS
+
+ use Text::Tabs;
+
+ $tabstop = 4;
+ @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. Invisible
+compression with plain ascii!
+
+=head1 BUGS
+
+expand doesn't handle newlines very quickly -- do not feed it an
+entire document in one string. Instead feed it an array of lines.
+
+=head1 AUTHOR
+
+David Muir Sharnoff <muir@idiom.com>