#!/usr/bin/perl -w

use strict;

use Getopt::Long qw( GetOptions );

# ----------------------------------------------------------------------

sub max ( @ )
{
    my $rv = $_[0];
    foreach my $v ( @_ )
    {
        $rv = $v if $v > $rv;
    }
    return $rv;
}

# ----------------------------------------------------------------------

my $OPT_W;
my $OPT_P;
my $OPT_F;

sub usage ( $ )
{
    my $reason = @_;

    die <<USAGE;
$0: $reason
usage: $0 [options] start [stop]
options:
   -w i    --width=i     make the numbers i digits wide
   -p 'c'  --pad='c'     pad with character c
   -f 's'  --format='s'  use 'printf'-style format s
USAGE
}

unless ( GetOptions( "w|width=i"  => \$OPT_W,
                     "p|pad=s"    => \$OPT_P,
                     "f|format=s" => \$OPT_F) )
{
    usage "unrecognized options";
}

if ( defined $OPT_P && length( $OPT_P ) != 1 )
{
    usage "-p must be exactly one character";
}

unless ( @ARGV == 1 || @ARGV == 2 )
{
    usage "need either one or two args";
}

# ----------------------------------------------------------------------

my ( $start, $stop ) = ( @ARGV, @ARGV );
my $inc = ( $start > $stop ) ? -1 : 1;
my $end_val = $stop + $inc;

my $width = defined( $OPT_W ) ? $OPT_W
                              : max( length( "$start" ),
                                     length( "$stop" ) );

my $pad_char = defined( $OPT_P ) ? $OPT_P : '0';

my $do_pad = defined( $OPT_W ) || defined( $OPT_P );

my $i = $start;
for ( my $i = $start; $i != $end_val; $i += $inc )
{
    if ( $OPT_F )
    {
        printf $OPT_F."\n", $i;
    }
    else
    {
        my $pad = $do_pad ? $pad_char x ( $width - length( "$i" ) ) : '';
        print $pad, $i, "\n";
    }
}

exit 0;