TwoStep

TwoStep is an esoteric programming language where each statement consists of two characters: a command character and a single digit (or other character). There are 12 commands, and it uses digits 0-9 and a single byte of memory.

Commands

Command	Function
+	Adds the given digit to the memory
-	Subtracts the given digit from the memory
/	Divide the memory by the given digit if the digit is not zero
*	Multiply the memory by the given digit
>	Do next statement if the given digit is less than the memory, otherwise skip over next statement
<	Do next statement if the given digit is greater than the memory, otherwise skip over next statement
)	Do previous statement if the given digit is less than the memory, otherwise skip over next statement
(	Do previous statement if the given digit is greater than the memory, otherwise skip over next statement
[	Output the ASCII character associated with the memory. Digit is ignored
]	Input an ASCII character store its code in the memory. Digit is ignored
.	Stop the program. Digit is ignored
	(space) No operation. Digit is ignored, so it can be used for comments

Examples

This program prints out "Hello, World!" Notice the comment at the beginning.

 H e l l o ,   W o r l d !  *0+6*2*6[ *0+5*5*4+1[ +7[ [ +3[ *0+5*9-1[ *0+8*4[ *0+9*9+6[ *0+5*5*4+9+2[ +3[ -6[ -8[ *0+8*4+1[ . 

This program runs an infinite loop that prints out "x".

*0+6*4*5[ )0. 

This cat program outputs its input.

] [ . 

It may be possible to create a quine in TwoStep, if you can manage to run the following program using the same byte of the memory the program is stored in. However, this program only uses a single character, instead of the required two, for the statement.

[

Interpreter

• Common Lisp implementation of the TwoStep programming language.