Argh!

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Argh! and Aargh! are fungeoid esoteric programming languages (i.e. languages deliberately designed to be strange, with utility not an objective).

Argh! and Aargh! share a two dimensional layout. Both are limited to 80 columns wide but while Argh! is also limited to 40 rows, Aargh! has unlimited number of rows. Each command is a single character and occupies one cell of the grid; a cell can alternately contain a value. The language also supports a stack of theoretically unbounded size. There are 27 documented commands.

The following program prints out "Hello, Wikipedia!": 

j       Wikipedia!
lpppppppPPPPPPPPPPq
 Hello,

Explanation of the above program: execution begins with the j in the top row leftmost column, which indicates the starting direction of execution is down. The next command executed is the l which means process commands to the right. Each p indicates that the value below it should be printed; each P that the value above it should be printed. The q (for quit) command marks the end of the program.

A program that tries to execute a value that is not a command, or that tries to execute outside the grid, emits the language's standard error message, Argh! or Aargh! as appropriate, and terminates.

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Commands

Each valid instruction in Argh! and Aargh! consists of one ASCII character. The can be classified as:

  • Unconditional flow control. There are 4 commands that specify which direction (left, down, up or right) instruction processing should proceed in.
  • Conditional flow control:
    • Jump to the next cell, in a specified direction, that has the same value as the top of the stack, and begin processing in that direction.
    • If value on top of stack is positive turn direction execution 90 degrees right; another command turns 90 degrees left if top value of stack is negative.
  • Stack operations:
    • Push value of cell above (or below) execution onto stack.
    • Duplicate top value of stack.
    • Pop and discard from stack.
    • Add/Subtract value in cell above/below this command to top of stack.
    • Pop value from stack and store in cell above/below this instruction.
  • Input/output:
    • Send value in cell above/below instruction to standard output.
    • Store byte from standard input in cell above/below this instruction.
    • Store system EOF in cell above/below this instruction.
  • End execution.
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External links

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