#!/bin/sh
#! -*- perl -*-
eval 'exec $PERLLOCATION/bin/perl -x $0 ${1+"$@"} ;'
 if 0;

sub _frameFrag {
	my(@frames)	= @_;

	my $numFrames = scalar(@frames);
	my $fragment;

	if ($numFrames == 0) {
		$fragment = undef;
	} elsif ($numFrames == 1) {
		$fragment = $frames[0];
	} else {
		# more than 2 frames in the sequence, so we should
		# break off everything we have so far.
		my $currInc = $frames[1] - $frames[0];

		my $firstFrame	= shift @frames;
		my $lastFrame	= pop @frames;
		my $fragment = $firstFrame . '-' . $lastFrame;
		if ($currInc != 1) {
			$fragment .= 'x' . $currInc;
		}
	}

	return $fragment;
}

$fragment = &_frameFrag(@ARGV);
if (defined($fragment)) {
	print $fragment,"\n";
}