manual.md

Whlplash

https://chat.stackexchange.com/rooms/123064/whlplash

https://github.com/ErmineII/whlplash

[toc]

Programs

A program is made up of (per source file):

• Optionally, a unnamed function without a header that will be run at program start.
• Any number of headers of the form @fn (a space, @, function name), each followed by a function body.
• A function body is a positive number of lines, which are split into cells two characters wide (a trailing single character is ignored). These lines must each either start with a non-space character or have a space as a second character.
• Any line may start with a space and a tilde ~, then implementation- specific directives.
• Any line may start with a space and a hash #. These lines will be ignored.

Commands

p	s	description
		no-op
n	n	literal number where ns are digits
.		Movement
	d	where d is in ><^v, change direction
	m	where m is in `
	#	jump forward over single instruction
	@	return/exit from program with exit code on top of stack or 0
	"	literal string like ."text" or ."text with odd characters!"
+		Arithmetic
	+	add top two numbers
	-	subtract top two numbers
	*	multiply top two numbers
	/	divide
	!	negate
?		Boolean stuff
	=	equal
	?	not equal (~ maybe)
	!	not
	<	less
	>	greater
	[	less or equal
	]	greater or equal
	#	jump forward if true
	j	relative jump if true (cond dx dy)
	J	conditional absolute jump
	*	top-of-the-stack times repeat next instr
	@	return if true
	d	if d is in {}^v turn <>^v respectively if the top of the stack is true
	`	`
	&	and
	X	xor
!		I/O and system commands
	.	output as default representation
	,	output as character
	?	system command
~		Stack manipulation
	:	dup ( a -- a a )
	~	swap/exch ( a b -- b a )
	r	rot ( a b c -- b c a )
	R	-rot ( a b c -- c a b )
	o	over ( a b -- a b a )
	t	tuck ( a b -- b a b )
	?	others?
:		Array commands
	+	append 2 arrays
	@	popping I then A push A[I]
	!	pops an array, index, and value and sets the value at the index in the array (I'm not sure of the order on the stack)
	]	pops N and collects the top N stack elements into an array
'	c	Push the literal character c

Questions

Implementation language?

Array datatype?

Of course there would be a sequence datatype, but how would it be represented? There could be malloc and free like in C. It should probably be 2d to fit the theme.

Popping off an empty stack?

• Error, because this is modern :P

Concurrency?

Probably not.

Wrapping

Horizontal wrapping, but errors instead of vertical wrapping.

Examples

Factorial

.>~:?!?v?:01+- F.+*.@  the " F"
  .@01.<

Fibonacci: (a b n -- fibonacci(n)) where a and b are 0 and 1 respectively for the normal sequence.

~:00?=?v~:01?=?v~R~t++~r
.@~$~$.<  ~r  .<