Using %alien.r and %alienexp.r

Source code originally by Unknown
Usage document written by Brian Tiffin, Library Team apprentice
24-Apr-2007

Contents:

1. Introduction to %alien.r and %alienexp.r

These two programs go hand in hand. The first, %alien.r is the obfuscated version of the (not much) clearer and easier to read %alienexp.r.

Obfuscate

make obscure or unclear.

Even the explanatory %alienexp.r is for advanced readers.

2. Reading more important than using

These two library scripts are important learning by example entries. As a beginner, the %alien.r source code is quite complicated and is better left as a thing to be revisited every once and a while as you learn more about REBOL programming.

When you get to a day where you can mentally apply the secret decoder ring to the %alien.r source code, you will no longer need the assistance of this apprentice in figuring out the scripts in the rebol.org repository.

When you get to a day when you can read through the %alienexp.r script, you will be well on your way to being a REBOL coder extrordinaire. Don't get stuck on it. Give these scripts a browse, note the weirdness and carry on with others.

2.1 No worries

Do not let any lack of understanding of these two scripts discourage your use of REBOL. Use them more as a shiny light at the end of a tunnel. A goal to be pursued, with the prize being understanding.

These two scripts are puzzles that even experts would find difficult, if not impossible, without reference to the secret decoder ring.

2.2 If you "got it" on first read.

If you did happen to understand the %alien.r source on the first read through, then you should dig right in and contribute to the REBOL community. You have a gift that few possess, and your contributions will be accepted with open arms by the few, the strong, the brave, that call REBOL ... home.

3. Using %alien.r

Seeing as this is a usage document, I should at least mention the usage.

From a REBOL console prompt, a simple

>>do %alien.r

will suffice to get the secret message.

3.1 Right out the library

REBOL being the powerful tool that it is, allows script execution right over the wire. The people at rebol.org have been kind enough to provide access to the scripts, through hypertext, with a set of REBOL programs. One of these programs is %view-script.r.

Again from a REBOL console prompt, you can type

>>do http://www.rebol.org/cgi-bin/cgiwrap/rebol/download-a-script.r?script-name=alienexp.r

and get the secret message without having a local copy of the source code.

Note how the output from %alien.r is identical to %alienexp.r. Such is the nature of secret decoder rings.