So basically if I create a digest based on the current XML file and a user alters it in some way I can raise a flag.

You wouldn't have any examples of this would you? :)

Thanks

It is as easy as:

use strict;

use Digest::file qw(digest_file_hex);

die 'XML file has been changed!\n'
    unless digest_file_hex( 'test.xml', "MD5" ) eq
        'e253b427caacb6f0781f337a90658c6a';
print "Continue\n";
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CountZero

A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James

Since XML is just text -- why not search for text compression? But to answer your question -- yes this seems very possible. But is it practical? What I don't understand, however, is why you give the users the ability to alter the contents in the first place. My solution would be to prevent them from having access to the files.

But search CPAN and see if one of the many archiving and compression modules suites your needs. Feel free to ask specific questions about which ever module you pick if you run into troubles (installing, using, etc.).

UPDATE: I like CountZero's suggestion. :)

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

Thanks jeffa,

I don't intentionally give users access but I'm afraid of the curious person poking at the install directory :)

You make a good point...I'm on a win32 box so I'm not sure how to restrict users from altering the files if they do find them.