#!/usr/bin/perl -wT

# Snippet of code written by Nigel Horne, Wharfedale Computers Ltd., B
+arnsley
# njh@despammed.com

# Routine to create and examine numeric ranges
# e.g. rangein 1 2 3 5 6 becomes 1-3 5 6
# and rangeout 1-3 5 6 becomes 1 2 3 5 6

# 20/8/02:      handle zeros

use strict;

# Pre-condition: The argument must be a sorted array of space separate
+d
#       unique numbers. This condition is not verified.
sub rangein {
        my $input = shift;
        my $max = -2;
        my $min = -2;

        foreach my $number (split(/ /, $input)) {
                if($number > $max + 1) {
                        if($max > $min + 1) {
                                print "$min-$max ";
                        } elsif($max == $min + 1) {
                                print "$min $max ";
                        } elsif($min >= 0) {
                                print "$min ";
                        }
                        $min = ($max = $number);
                } elsif($number == $max + 1) {
                        $max++;
                } else {
                        $min = ($max = $number);
                }
        }
        if($max > $min + 1) {
                print "$min-$max ";
        } elsif($max == $min + 1) {
                print "$min $max ";
        } elsif($min >= 0) {
                print "$min ";
        }
        print "\n";
}

sub rangeout {
        my $input = shift;

        foreach my $range (split(/ /, $input)) {
                if($range =~ /(.+)-(.+)/) {
                        foreach ($1..$2) {
                                print "$_ ";
                        }
                } else {
                        print "$range ";
                }
        }
        print "\n";
}

print "testing rangein...\n";

&rangein("0 1 3 4 5 7 ");
&rangein("1 3 4 5 7 ");
&rangein("1 ");
&rangein("1 3 ");
&rangein("1 2 3 ");
&rangein("1 2 3 4 6 7 8 ");

print "testing rangeout...\n";

&rangeout("0 1 3-5 7 ");
&rangeout("1 3-5 7 ");
&rangeout("1 ");
&rangeout("1 3 ");
&rangeout("1-3 ");
&rangeout("1-4 6-8 ");
[download]