Evil

From Esolang

The title of this article is incorrect because of technical limitations. The correct title is evil.

evil is a minimal language of the line-noise school. It was devised by Tom Wrensch in about 1999, while he was a graduate student at the University of Colorado.

Commands in evil are lower case letters. Upper case letters are reserved for future library calls. Other characters are ignored. So every text file is a legal evil program, making documentation a challenge.

The evil computation model involves a single register, called A, that can store a single byte, a state bit specifying one of two jump destination markers (standard or alternate) and three memory pools: the source code, the wheel, a variable-sized circular list of bytes and the pental, a second wheel whose size is fixed at five. Each of the pools is addressed through a pointer register. A most useful control-flow command is q, which swaps the wheel and the source code, allowing for run-time code generation and other sins.

Here is a Hello, world! program in evil.

   zaeeeaeeew
   zaeeaeeaeaw
   zaeaeeaeeaew
   zaeaeeaeeaew
   zuueeueew
   zaeeeeew
   zuueueueeeew
   zuueeueew
   zaeeaeeaeaeew
   zaeaeeaeeaew
   zaeeaeeaew
   zaeeeeeaw
   zaeeeeeaeawuuuw

It constructs the ASCII values of the characters in the A register and writes them out using the w command. The z command zeros A, the a command increments A, the e command shuffles A's bit order from 76543210 to 64725031, and u decrements A.