Random

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Random, standing for R and O Machine(temporarily R & O refers to Regenerating & Overrunning, but subjects to change looking forward any better idea) is a minimalistic esoteric programming language in string-rewriting paradigm, assuming the source code itself as a double-ended stack. First proposed by User:Gs30ng, the specification is under development yet.

Overview

Based on a linear memory space which is the source code itself, a Random program deals with six kinds of instruction:

<
>
[
]
><
And all other characters

Interpretation starts from the left side of the code.

  • All characters except for <, >, [, ] and >< are simple instructions: Add itself to the back(right side) of the code. Therefore a simple infinite loop can be written as an anonymous one character:
A
AA
AAA
AAAA
AAAAA
...
  • Instruction < pops an element from the back of the code, and pushes it onto the front of the code.
A<<B
A<<BA
AA<<B
BAA<<
  • Instruction > pops a element from the front of the code, and pushes it onto the back of the code.
  • [...] can be written as "Do ... while the front element and the back element are different" in pseudo-code. [ transfers the control to corresponding ] if the front element of the code and the back element are same. ] transfers the control to corresponding [ if the front and back element are different. If there is no corresponding [ or ], the program terminates.
  • Since >< is NOP, making it another instruction does not cause any collide. In Random this instruction pops an element from the back and prints it out.

Example codes

!dlroW ,olleH[><]><

prints "Hello, World!".

Computational class

Since a Random program can push/pop items onto/from the both sides of the code, it can simulate a machine with 2 stacks. At this time it is not sure but it is guessed that Random can simulate the Turing machine.

External resources