mercury/samples/rot13

This directory contains various implementations of `rot13', which
is a simple encryption technique.

From the Jargon File: 

        rot13 /rot ther'teen/ /n.,v./ [Usenet: from `rotate alphabet
    13 places'] The simple Caesar-cypher encryption that replaces each
    English letter with the one 13 places forward or back along the
    alphabet, so that "The butler did it!" becomes "Gur ohgyre qvq vg!"
    Most Usenet news reading and posting programs include a rot13
    feature. It is used to enclose the text in a sealed wrapper that the
    reader must choose to open -- e.g., for posting things that might
    offend some readers, or {spoiler}s. A major advantage of rot13 over
    rot(N) for other N is that it is self-inverse, so the same code can
    be used for encoding and decoding.

The different implementations are intended to show different styles
of Mercury programs, and different trade-offs that can be made
between conciseness, readability, correctness, error-handling, etc.

To build these samples, install the Mercury compiler and type
	mmake depend
	mmake