#!/share/bin/perl -w

# This is the example for the "key word in context" listing.
# It reads a file of text records, e.g. of film titles, one record per line
# Each Capitalized word on a line is a keyword
# The program is to produce a key word in context listing with
# the keywords lining up around column 50 of the output page

# The output lines are composed, the keyword starts at column 50
# This special sort helper function compares substrings starting at this point
sub by_keystr {
	my $str1 = substr($a,50);
	my $str2 = substr($b,50);
	if($str1 lt $str2) { return -1; }
	elsif($str1 eq $str2) { return 0; }
	else { return 1; }
}

# main program starts here
@collection = ();
while($title = <STDIN>) {
	chomp($title);
	# split line into words at space characters
	@Title = split / / , $title;
	$start = "";
	foreach $i (0 .. $#Title) {
		$Word = $Title[$i];
		# Simple pattern test, does word start with a capital letter
		if($Word =~ /^[A-Z]/) {  
			$end = "";
			# There are neater ways of building this list!
			for($j=$i;$j<=$#Title;$j++) 
				 { $end .= $Title[$j] . " "; }
			# Use formatted print routine
			$line = sprintf "%50s   %-50s\n", $start, $end;
			push(@collection, $line);
		}

		$start .= $Word . " ";
	}
}

@sortcollection = sort by_keystr @collection;
foreach $entry (@sortcollection) {
	print $entry;
}