Whitespace

Whitespace is a strange language. Its tokens are space, line-feed, and tab — everything else is comment. It's stack based, has console i/o, and an associative store. Yes, it's Turing complete. Yes, you'd be insane to use it. It belongs to the venerable tradition of languages like Brainf*ck, Shakespeare, and Unlambda.

Here's my Whitespace interpreter, written in Ruby. It's nothing to be proud of, but hey, what do you expect at 4 a.m.?

I stayed up for the better part of a night writing this. Why? Crazy, I guess.

Whitespace-asm

Here's my whitespace assembler, also written in Ruby.

This test program prints the alphabet: alphabet.wsa

To assemble it, run whitespace-asm like this:

./whitespace-asm alphabet.wsa

That should generate alphabet.ws.

Then run it:

./whitespace alphabet.ws ABCDEFGHIJKLMNOPQRSTUVWXYZ

Syntax

Comments

A "#" anywhere on a line starts a comment. The rest of the line is ignored. Blank lines are ignored.

Labels

You can use this alternate syntax for a label if you wish:

unsigned-number:

Opcodes

Opcode Operand Description

Stack Manipulation push signed-number Push a number onto the stack

dup Push top of stack into the stack again

swap Swap two topmost numbers on stack

discard Pop & discard number on top of stack

Arithmetic add Pop two numbers, add, push result

sub Pop two numbers, subtract, push result

mul Pop two numbers, multiply, push result

div Pop two numbers, integer divide, push result

mod Pop two numbers, modulo, push result

Heap Access store Pop value and address; store value on heap at that address

retrieve Pop address; push onto stack the heap value at that address

Flow Control label unsigned-number Target for other flow-control ops

call unsigned-number Call subroutine

jump unsigned-number Unconditional jump

jz unsigned-number Pop top of stack; jump if it's zero

jn unsigned-number Pop top of stack; jump if it's negative

ret Return from subroutine

exit Exit interpreter

I/O outchar Pop top of stack; print it as ascii character

outnum Pop top of stack; print it as decimal number

readchar Read character from stdin & push it onto stack

readnum Read integer from stdin & push it onto stack

Opcode	Operand	Description
Stack Manipulation	push	signed-number	Push a number onto the stack
dup		Push top of stack into the stack again
swap		Swap two topmost numbers on stack
discard		Pop & discard number on top of stack
Arithmetic	add		Pop two numbers, add, push result
sub		Pop two numbers, subtract, push result
mul		Pop two numbers, multiply, push result
div		Pop two numbers, integer divide, push result
mod		Pop two numbers, modulo, push result
Heap Access	store		Pop value and address; store value on heap at that address
retrieve		Pop address; push onto stack the heap value at that address
Flow Control	label	unsigned-number	Target for other flow-control ops
call	unsigned-number	Call subroutine
jump	unsigned-number	Unconditional jump
jz	unsigned-number	Pop top of stack; jump if it's zero
jn	unsigned-number	Pop top of stack; jump if it's negative
ret		Return from subroutine
exit		Exit interpreter
I/O	outchar		Pop top of stack; print it as ascii character
outnum		Pop top of stack; print it as decimal number
readchar		Read character from stdin & push it onto stack
readnum		Read integer from stdin & push it onto stack

Whitespace-disassem

Here's my whitespace disassembler. It's nothing more than a cheap hack of my interpreter.

Yes, there's too much duplicated code between these three programs. No, I'm not going to fix it tonight. Maybe tomorrow.