use strict; use warnings; package Text::Tabs; BEGIN { require Exporter; *import = \&Exporter::import } our @EXPORT = qw( expand unexpand $tabstop ); our $VERSION = '2024.001'; our $SUBVERSION = 'modern'; # back-compat vestige our $tabstop = 8; sub expand { my @l; my $pad; for ( @_ ) { defined or do { push @l, ''; next }; my $s = ''; for (split(/^/m, $_, -1)) { my $offs; for (split(/\t/, $_, -1)) { if (defined $offs) { $pad = $tabstop - $offs % $tabstop; $s .= " " x $pad; } $s .= $_; $offs = /^\pM/ + ( () = /\PM/g ); } } 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) { defined $x or next; @lines = split("\n", $x, -1); for $line (@lines) { $line = expand($line); @e = split(/((?:\PM\pM*|^\pM+){$tabstop})/,$line,-1); $lastbit = pop(@e); $lastbit = '' unless defined $lastbit; $lastbit = "\t" if $lastbit eq $ts_as_space; for $_ (@e) { s/ +$/\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 like 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 most of what the unix utilities expand(1) and unexpand(1) do. Given a line with tabs in it, C replaces those tabs with the appropriate number of spaces. Given a line with or without tabs in it, C adds tabs when it can save bytes by doing so, like the C command. Unlike the old unix utilities, this module correctly accounts for any Unicode combining characters (such as diacriticals) that may occur in each line for both expansion and unexpansion. These are overstrike characters that do not increment the logical position. Make sure you have the appropriate Unicode settings enabled. =head1 EXPORTS The following are exported: =over 4 =item expand =item unexpand =item $tabstop The C<$tabstop> variable controls how many column positions apart each tabstop is. The default is 8. Please note that C doesn't do the right thing and if you want to use C to override C<$tabstop>, you need to use C. =back =head1 EXAMPLE #!perl # unexpand -a use Text::Tabs; while (<>) { print unexpand $_; } Instead of the shell's C command, use: perl -MText::Tabs -n -e 'print expand $_' Instead of the shell's C command, use: perl -MText::Tabs -n -e 'print unexpand $_' =head1 BUGS Text::Tabs handles only tabs (C<"\t">) and combining characters (C). It doesn't count backwards for backspaces (C<"\t">), omit other non-printing control characters (C), or otherwise deal with any other zero-, half-, and full-width characters. =head1 LICENSE Copyright (C) 1996-2002,2005,2006 David Muir Sharnoff. Copyright (C) 2005 Aristotle Pagaltzis Copyright (C) 2012-2013 Google, Inc. This module may be modified, used, copied, and redistributed at your own risk. Although allowed by the preceding license, please do not publicly redistribute modified versions of this code with the name "Text::Tabs" unless it passes the unmodified Text::Tabs test suite.