DominoScript

Current version 0.5.0

Have you ever wanted to write code using domino pieces? No?

Well, now you can! Introducing DominoScript!

Note

A recreational stack-oriented concatenative two-dimensional non-linear self-modifying int32-based esoteric programming language that uses the dots on domino pieces to represent code.

This repository contains the reference implementation written in TypeScript as well as all the documentation and examples for the language.

Try it in the Online Playground.

It's still very much a work-in-progress. Not everything is fully fleshed out yet. Do you want to contribute?

Table of Contents

• Core Concepts

• How to run DominoScript

• How does it work

  • Text Format
  • About the stack
  • How to represent Strings
  • How to represent floating point numbers
  • How the Instruction Pointer Moves
  • How Navigation Modes work
  • How to read DominoScript

• Instructions

  • Stack Management
  • Arithmetic
  • Comparison & Logical
  • Bitwise
  • Control Flow
  • Input & Output
  • Misc

• Navigation Modes

  • Basic Three Way
  • Basic Two Way
  • Basic One Way
  • Cycle Three Way
  • Cycle Two Way
  • Cycle One Way
  • Flip Flop

• Error Types

• Contributing

• Roadmap

• Examples

Core Concepts

• Recreational Esolang: This isn't a serious programming language. I got inspired after watching "The Art of Code" by Dylan Beattie where I discovered "Piet" and eventually went down the esolang rabbit hole. I wanted to create a language that is not only weirdly powerful but can also look good when hanged on a wall.

• Stack-Oriented: There is a global data stack that all instructions operate on. Internally every item on the stack is a signed 32-bit integer. Strings are just null-terminated sequences of integers representing Unicode char codes. Floats are not supported. No other data structures exist.

• Concatenative: DominoScript at its core is just another concatenative reverse-polish language. The following code: 0—1 0—5 0—1 0—6 1—0 0—3 1—2 5—1 is the same as 5 6 + dup * . in Forth.

• Two-Dimensional: The code is represented on a rectangle grid. The instruction pointer can move in any cardinal direction. One domino takes up 2 cells on the grid. Direction changes are performed by placing dominos in a certain way (IP always moves from one half to the other half of the same domino) as well as the current Navigation Mode.

• Self-Modifying: The code can override itself similar to befunge.

• Òbfuscated: Because all code is represented using domino pieces, reading it is somewhat like reading machine code. To "de-obfuscate" it you would need to replace the domino pieces with their corresponding instructions and literal values. The following: NUM 5 NUM 6 SUM DUPE MULT NUMOUT is a readable pseudocode representation of DominoScript.

How to run DominoScript

Warning

Despite being well tested, the reference interpreter might not always work as expected. See the Source code.

The easiest way to run DominoScript is the Online Playground (early prototype, might be more buggy than running it via the command line...).

However, if you want to use dominoscript via the command line, you can install it globally like this:

npm install -g dominoscript

Then you can run it like this:

dominoscript path/to/your/file.ds

Or you can use npx to run it without installing it:

npx dominoscript path/to/your/file.ds

How does it work

DominoScript by default uses Double-Six (aka D6) dominos to represent code. Double-six here means that each domino has 2 sides with up to 6 dots on each side.

Everything is either:

• an instruction
• a number literal
• or a string literal

Using Double-Six dominos, we are essentially working with base7 numbers. This can be changed using the BASE instruction.

With a higher base you can use dominos with more dots to represent larger numbers with fewer pieces.

The Grid

• The grid is a rectangle of cells which can contain domino pieces.
• The grid can contain up to 65408 cells (soft limit)
• One domino takes up 2 cells and can be placed horizontally or vertically.
• The top-left cell is address 0. The bottom-right cell is address width * height - 1.
• When playing domino game variants you can usually place pieces "outside" the grid when both sides have the same number of dots: 🁈🁳🁀 - this is not allowed in DominoScript (Maybe in future versions but for now not worth the extra complexity)

Each cell needs to be indexable using an int32 popped from the stack, so in theory you could have something crazy like a 300k rows and columns. However, the interpreter will likely not be able to handle that. The artifical limit I decided on for now is a total of 65408 cells. That allows a square grid of 256x256 or various rectangular grids like 64x1024, 128x512, or 949x69 as long as the total cell count is 65408 or less. This limit will likely be configurable in future versions.

Text Format

A text based format is used to represent domino pieces.

Note

This format is used as source code. At the beginning it will be the only way to write DominoScript until a visual editor is created that shows actual dominos. Eventually I want to be able to convert images of real dominos on a (reasonably sized) grid into the text format.

• The digits 0 to f represent the dots on half of a domino. To indicate an empty cell, use a dot .
• The "long hyphen" character — indicates a horizontal domino (regular hyphen - also accepted to make it easier to type). It can only appear on even columns and odd rows.
• The "pipe" character | indicates a vertical domino. It can only appear on odd columns and even rows.
• Any other line before and after the actual code is ignored.
• It is just a text format, so the file extension doesn't matter for now. You can make it .md and comment using markdown if you want! See example

Example:

TITLE
=====

You can write the soure code as a normal text file (.ds extension recommended) or as a .md file with markdown comments like here.

Be aware of the following rules:
> 1. You cannot start a non-code line with a dot `.`
> 2. You cannot start a non-code line with a number `0 to f`
> 3. You cannot comment within the code. Only above and below it.

For comments starting with any non-allowed character, add a space or any other allowed char before it.

## DominoScript

The below code NO-OPs forever because
The IP can always move to a new domino

. . . . . . . .

. 6 6 6—6 6 6 .
  | |     | |
. 6 6 6 6 6 6 .
      | |
. 6—6 6 6 6—6 .

. 6—6 6—6 6—6 .

. . . . . . . . 


## Some Notes

Bla bla bla
  

When the source code is parsed it ignores everything except the actual code:

. . . . . . . .

. 6 6 6—6 6 6 .
  | |     | |
. 6 6 6 6 6 6 .
      | |
. 6—6 6 6 6—6 .

. 6—6 6—6 6—6 .

. . . . . . . . 

Which is the equivalent of these dominos:

The grid doesn't have to be a square but it must have a consistent number of columns and rows, otherwise an InvalidGridError will be thrown before execution starts:

GOOD ✅	BAD ❌
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . .

Connecting to a domino half which is already connected results in MultiConnectionError:

GOOD ✅	BAD ❌
6—6 6—6 . 6 6—6 . . | 6 . . . .	6—6—6—6 . 6—6 . . . | 6 . . . .

Having a domino half that is not connected to anything results in MissingConnectionError:

GOOD ✅	BAD ❌
. . 6—6 . . 6 . . . | . 6 . . .	. . 6 6 . . 6 . . . . 6 . . .

Having a connection where 1 or both ends are empty results in a ConnectionToEmptyCellError:

GOOD ✅	BAD ❌
6—6 . 6—6 6 . . . 6 | | 6 . . . 6	6—. . .—6 6 . . . . | | . . . . 6

About the stack

• There is a single global stack that all instructions operate on.
• It only stores signed 32-bit Integers
• The interpreter will preallocate all the memory required to maintain the stack, therefore its size is limited to 512 items for now. (No particular reason for this rather small limit, it will likely be configurable in future versions)

Why not 64-bit integers?: No good reason really. I wanted to implement the first reference interpreter in typescript and since JS converts numbers to 32-bit when doing bitwise operations, I decided to just stick with 32-bit integers instead of having to split the lower and upper 32-bits for every bitwise operation. If there is demand, I will change the spec to support 64-bit ints but for now it is what it is.

How to represent Strings

DominoScript is a language where you cannot really tell what is going on just by looking at the code. It all depends on how the IP moves.

When the IP encounters a STR instruction, it will parse the next dominos as characters of a string. How that works exactly is explained in more detail in the description of the instruction.

Important

It is important to understand that internally everything in DominoScript is represented as signed 32-bit integers and externally everything is represented by the dots on the domino pieces.

Internally strings are just null-terminated sequences of integers representing Unicode char codes. It is your job as the developer to keep track of which items on the stack are numbers and which ones are characters of a string.

You can use any instruction on characters of a "string" but most of them will not distinguish between what is a number and a character.

So far, there are only 7 instructions which are meant for the handling of strings: STR, EQLSTR, STRIN, STROUT as well as GET and SET when used with a specific "type" argument.

In examples, you might see stack items that are meant to be char codes, represented in the following way:"

[..., 'NUL', 's', 'e', 'y']

But in reality, the stack will store them as integers and look like this:

[..., 0, 115, 101, 121]

How to represent floating point numbers

Floats don't exist in DominoScript. I'd suggest to scale up numbers by a factor of 10, 100, 1000 or whatever precision you need.

(I know that pico-8 uses 32-bits for numbers but treats them as 16.16 fixed point numbers. I am not quite sure if that is just a convention or if pico8's API actually treats them as fixed point numbers. I would like to eventually add some trigonometry instructions to DominoScript but am unsure what the most practical way would be)

How the Instruction Pointer Moves

The instruction pointer (IP) keeps track of the current cell address that will be used for the next instruction. Since DominoScript is 2D and non-linear, it isn't obvious where the IP will move to without understanding the fundamental rules and the Navigation Modes.

Before the program starts:

• the interpreter will scan the grid from top-left to top-right, move down and repeat until it finds the first domino.
• Upon reaching the first domino, the IP is placed at the address of the first found domino half.
• If no domino could be found, the program is considered finished.

During the program execution: The IP will adhere to the following rules:

• Rule_01: The IP moves in all cardinal directions, never diagonally. How dominos are parsed, is all relative to that. For example, the horizontal domino 3—5 can be interpreted as the base7 number 35 (IP moves eastwards) or 53 (IP moves westwards). Same thing for vertical dominos.

• Rule_02: The IP will always move from one half (entry) of the same domino to the other half (exit) of the same domino.

• Rule_03: If the IP cannot move to a new domino, the program is considered finished. If a JUMP happens to move to an empty cell, a JumpToEmptyCellError is thrown and the program terminates with a non-zero exit code.

• Rule_04: At the exit half of a domino, the IP will never move back to the entry half. It will always try to move to a new domino. That means, there are at most 0 to 3 potential options for the IP to move.

• Rule_05: When the IP needs to move to a new domino, it is possible that there are no valid moves despite there being dominos around. The Navigation Mode decides where the IP can and cannot move next.

How Navigation Modes work

In a nutshell: Navigation Modes are predefined priority patterns which change the way the Instruction Pointer moves.

Tip

Change navigation modes using the NAVM instruction.

First I'm gonna bombard you with some jargon:

• Priority Directions (PDs): Primary, Secondary, Tertiary
• Relative Directions (RDs): Forward, Left, Right
• Cardinal Directions (CDs): North, East, South, West

The Cardinal directions don't matter much. It is all about the direction in relation to the exit half of the current domino (If you ever did any kind of game dev you probably know the difference between world space and local space. It's kind of like that)

When the IP moves to a new domino, the half it enters to is called the "entry" while the other half is called the "exit". Now from the perspective of the exit half, the IP can potentially move in 3 directions: Forward, Left, Right. These are the Relative Directions (RDs).

Which direction it chooses, depends on the current "Navigation Mode". Here are some of the most basic Nav Mode mappings:

index	Primary	Secondary	Tertiary
0	Forward	Left	Right
1	Forward	Right	Left
2	Left	Forward	Right
3	Left	Right	Forward
4	Right	Forward	Left
5	Right	Left	Forward
...	...	...	...

The "index" here is the argument for the NAVMinstruction.

If we imagine the 6 to be the exit half, what will be the next domino the IP moves to?:

East	West	South	North
. 2 . . . | . 2 . . . 5—6 1—1 . . 3 . . . | . 3 . . .	. . . 3 . | . . . 3 . . 1—1 6—5 . . . 2 . | . . . 2 .	. . 5 . . | 3—3 6 2—2 . . 1 . . | . . 1 . . . . . . .	. . . . . . . 1 . . | . . 1 . . 2—2 6 3—3 | . . 5 . .

All 4 snippets are exactly the same code with the difference that they are all flipped differently. This is what I mean by the cardinal direction not mattering much in DominoScript.

• When index 0, the IP will move to 1—1 (Primary, Forward)
• When index 1, the IP will move to 1—1 (Primary, Forward)
• When index 2, the IP will move to 2—2 (Primary, Left)
• When index 3, the IP will move to 2—2 (Primary, Left)
• When index 4, the IP will move to 3—3 (Primary, Right)
• When index 5, the IP will move to 3—3 (Primary, Right)

What if we remove the 1—1 domino? Where will the IP go to then?:

East	West	South	North
. 2 . . . | . 2 . . . 5—6 . . . . 3 . . . | . 3 . . .	. . . 3 . | . . . 3 . . . . 6—5 . . . 2 . | . . . 2 .	. . 5 . . | 3—3 6 2—2 . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . 2—2 6 3—3 | . . 5 . .

• When index 0, the IP will move to 2—2 (Secondary, Left)
• When index 1, the IP will move to 3—3 (Secondary, Right)
• When index 2, the IP will move to 2—2 (Primary, Left)
• When index 3, the IP will move to 2—2 (Primary, Left)
• When index 4, the IP will move to 3—3 (Primary, Right)
• When index 5, the IP will move to 3—3 (Primary, Right)

And what if we remove both the 1—1 and the 2—2 domino?:

East	West	South	North
. . . . . . . . . . 5—6 . . . . 3 . . . | . 3 . . .	. . . 3 . | . . . 3 . . . . 6—5 . . . . . . . . . .	. . 5 . . | 3—3 6 . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . 6 3—3 | . . 5 . .

• When index 0, the IP will move to 3—3 (Tertiary, Right)
• When index 1, the IP will move to 3—3 (Secondary, Right)
• When index 2, the IP will move to 3—3 (Tertiary, Right)
• When index 3, the IP will move to 3—3 (Secondary, Right)
• When index 4, the IP will move to 3—3 (Primary, Right)
• When index 5, the IP will move to 3—3 (Primary, Right)

These are only variations of the "Basic-Three-Way" kind of NavModes. See the Reference for a full list of available modes.

How to read DominoScript

DS isn't meant to be easily human readable but there are patterns that, once you recognize them, will make it much easier to understand what is going on.

All of these patterns revolve around how the NUM and STR instructions behave differently than any other instruction.

Once you understand how they are different, reading the rest of DominoScript is mostly a matter of keeping track of how the other instructions affect:

• the Stack (most of them do)
• the Instruction Pointer (e.g. JUMP, CALL, NAVM).
• The way Domino pieces are parsed (e.g. LIT, BASE, EXT)

The following patterns and examples assume that the default LIT mode was not changed:

Tip

PATTERN 1:

Look out for 0—1 and 0—2 dominos.

These are often opcodes for the NUM and STR instructions and indicate the start of a number literal or a string literal (unless they themselves are part of a literal).

Tip

PATTERN 2:

Look out for the first half of a domino right after a NUM instruction.

If the default LIT mode was not changed, they will decide how many more dominos will be part of the number literal before the next instruction is executed.

The below code results in the number 6 being pushed and popped of the stack:

0—1 0—6 0—0

• 0—1 is a NUM instruction (PATTERN 1)
• 0—6 is the number literal
  • first half is 0 which, in default LIT mode, means no more dominos will follow and only the second half is parsed as a literal value (see PATTERN 2)
  • Second half is 6 in both base7 and decimal so the decimal number 6 is pushed to the stack
• 0—0 is the next instruction. We know that because the first half of previous domino told us that no more dominos will be part of the literal. (see PATTERN 2)

The below code results in the number 1000 being pushed and popped off the stack:

0—1 2—0 2—6 2—6 0—0

• 0—1 is a NUM instruction (see PATTERN 1)
• 2—0 2—6 2—6 is parsed as a literal value.
  • the first half is 2, which means 2 more dominos will be parsed as a literal value (see PATTERN 2)
  • the remaining 2.5 dominos are parsed as 2626 in base7 which is 1000 in decimal.
  • 0—0 is the next instruction. We know that because the first half of the domino after NUM told us that 2 more dominos will be parsed as part of the number literal, so 3rd one after will be an instruction (see PATTERN 2).

Tip

PATTERN 3:

While in default LIT mode, look out for the first half of a domino right after a STR instruction.

For the same reason as after a NUM instruction. It will decide how many more dominos will be part of the character before the next character of the string literal is parsed.

Tip

PATTERN 4:

Look out for the NULL terminator 0—0 during a STR instruction.

It indicates that the string literal is complete and that the next domino will be parsed as an instruction.

The below code results in the string "abc" being pushed to the stack.

0—2 1—1 6—6 1—2 0—0 1—2 0—1 0—0 0—1 0—6 0—0

• 0—2 is a STR instruction
• 1—1 6—6 is the Unicode value for "a"
• 1—2 0—0 is the Unicode value for "b"
• 1—2 0—1 is the Unicode value for "c"
• 0—0 is the null terminator. We know that because STR only ends once it encounters a 0—0 (see PATTERN 4)
• 0—1 0—6 0—0 is the code from the first example above. It will push the number 6 to the stack and then pop it off again (notice how the same amount of dots can mean different things depending on the context!)

The patterns are valid for all cardinal directions the Instruction Pointer can move in.

You have to understand, that the same domino can represent something completely different depending on the direction it is read from and what instruction preceded it.

0—1 . 1—0 . 1 . 0 . . .
            |   |
. . . . . . 0 . 1 . . .

The above domino can be interpreted as either a 10 or a 1. A 10 can mean different values depending on the current BASE (e.g. in base7 a 10 is 7 in decimal, in base16 a 10 is 16 in decimal). If a NUM or a STR instruction directly preceeded it, they are interpreted as literal values. If not, they are interpreted as opcodes.

Instructions

The "core" instruction set consists of 49 opcodes and is meant to fit within the value range a single "double-six" domino can represent (0 to 48).

In the below overview, you can see the instructions on a 7x7 matrix representing the "opcode-to-instruction" mapping while in the default base7 mode (Base7 means "double-six" dominos are used which can have 0 to 6 dots on each half).

Important

Keep in mind that if you change into a higher BASE, you will need to use different dominos to represent the same opcode!

The images of dominos shown alongside each instruction, are only valid while in base7 mode.

For example: The opcode for NOOP is 48 in decimal. To represent it in base7, a 6—6 domino is used. To represent it in base16, a 3—0 domino is used.

If that is too confusing, I recommend to simply switch to base10 mode where the decimal number 48 (aka the opcode for NOOP) is represented by a 4—8 domino.

	0	1	2	3	4	5	6	CATEGORY
0	POP	NUM	STR	DUPE	ROLL	LEN	CLR	Stack Management
1	ADD	SUB	MULT	DIV	MOD	NEG	CLAMP	Arithmetic
2	NOT	AND	OR	EQL	GTR	EQLSTR	_	Comparison & Logical
3	BNOT	BAND	BOR	BXOR	LSL	LSR	ASR	Bitwise
4	NAVM	BRANCH	LABEL	JUMP	CALL	IMPORT	WAIT	Control Flow
5	NUMIN	NUMOUT	STRIN	STROUT	KEY	KEYRES	_	Input & Output
6	GET	SET	LIT	BASE	EXT	TIME	NOOP	Misc

(DominoScript isn't limited to these 49 instructions. Opcodes 0-99 are reserved for "official" instructions, while opcodes 100+ can be used to extend the language using the LABEL instruction as well as eventually via the JS API. TODO explain in more detail.)

Stack Management

POP

Discards the top of the stack.

NUM

Switch to "number mode". By default the first half of the next domino will indicate how many dominos to read as a number. Then the other halfs will all be read as base7 digits (in D6 mode) to form the number that will be pushed to the stack.

With 7 dominos, 13 out of 14 halfs are used for the number. You can theoretically represent a number much larger than the max int32 value. However, if the number exceeds the maximum int32 value, it will wrap around from the minimum value, and vice versa (exactly the same as when doing bitwise operations in JS --> (96889010406 | 0) === -1895237402).

You might think that since internally numbers are int32s, that we parse from base7 to two's complement. That is not the case. We simple push the decimal version of the positive base7 number to the stack

For example:

• 0—0 represents the number 0 in both decimal and base7
• 0—6 represents the number 6 in both decimal and base7
• 1—6 6—6 represents the number 342 in decimal and 666 in base7
• 2—6 6—6 6—6 represents the number 16,806 in decimal and 6,666 in base7
• 6—6 6—6 6—6 6—6 6—6 6—6 represents the number 1,977,326,742 in decimal and 66,666,666,666 in base7 (about 92.1% of the max int32 value)
• 6—0 1—0 4—1 3—4 2—1 1—1 6—1 represents the number 2,147,483,647 in decimal and 104,134,211,161 in base7 (exactly the max int32 value)
• 6—6 6—6 6—6 6—6 6—6 6—6 6—6 represents the number -1,895,237,402. WHY?: The actual decimal number the dominos represent is 96,889,010,406 which is ~45x larger than the max int32 value. It wraps around about that many times before it reaches the final value.

What if numbers are read from the other direction?

• 1—1 1—1, 2—2 2—2 2—2 for example will be exactly the same numbers (216 in decimal) eastwards and westwards.
• 1—2 3—1 when parsed backwards is 1—3 2—1 and can therefore represent different numbers if the IP moves to the east or to the west.
• 1—6 6—6 represents 666 in base7 (342 in decimal) but when parsed backwards the interpreter will raise an UnexpectedEndOfNumberError. Remember that the first half of the first domino indicates how many more will follow. In this case it expects to read 6 more dominos but the number ends prematurely after 1 domino.

To push the number 10 and 5 to the stack you would use the following dominos:

• In pseudo code: NUM 10 NUM 5
• In DominoScript: 0—1 1—0 1—3 0—1 0—5
  • 0—1 is NUM
  • 1—0 1—3 is the number 13 in base7 which is 10 in decimal
  • 0—1 is NUM again
  • 0—5 is the number 5 in both base7 and decimal

To push the number -10 and -5 to the stack you would use the following dominos:

• In pseudo code: NUM 10 NEG NUM 5 NEG
• In DominoScript: 0—1 1—0 1—3 1—5 0—1 0—5 1—5
  • 0—1 is NUM
  • 1—0 1—3 is 13 in base7 which is 10 in decimal
  • 1—5 is NEG
  • 0—1 is NUM again
  • 0—5 is 5 in both base7 and decimal
  • 1—5 is NEG

What if I want to use a fixed amount of dominos for each number?

Use the LIT instruction to permanently change how literals are parsed. For example with parse mode 2 it will use 2 dominos for each number. While 6—6 6—6 in default parse mode 0 results in UnexpectedEndOfNumberError (because it expects 6 more dominos to follow but only got 1 more), in parse mode 2 it represents the decimal number 2400.

STR

With STR you switch to "string mode" and can push multiple integers to the stack to represent Unicode characters.

The way the dominos are parsed to numbers is identical to NUM: First half of first domino indicates how many more will follow for a single number.

The difference is that it doesn't stop with just one number. It will keep reading numbers until it encounters the NULL character represented by domino 0—0.

Only once the interpreter does encounter the NULL character, will it push the characters to the stack in reverse order.

(Note: I decided to parse strings like this because I wanted a single int32 based stack and, out of all options I could think of, this one felt the least annoying. If you can think of better ways, I am open for suggestions!)

This is how you push the string "hi!" to the stack and output it:

0—2 1—2 0—6 1—2 1—0 1—0 4—5 0—0 5—3

It equals the following pseudo code: STR "hi!" STROUT

• 0—2 is the STR instruction
• 1—2 0—6 is the Unicode value 105 representing the character h
• 1—2 1—0 is the Unicode value 105 representing the character i
• 0—0 4—5 is the Unicode value 33 representing the character !
• 0—0 is the Unicode value for the NULL character which terminates the string.
• 5—3 is the STROUT instruction. It will pop items from the stack, parse them as Unicode chars and once it encounters the NULL character, it will output the string to stdout all at once.

This is the resulting stack:

Imaginative	Reality
[..., 'NUL', '!', 'i', 'h']	[..., 0, 33, 105, 104]

Keep in mind that the IP can move in 4 cardinal direction so the following variations would also push the string "hi!" to the stack:

IP moves right to left:

3—5 0—0 5—4 0—1 0—1 2—1 6—0 2—1 2—0

IP moves in multiple directions:

0 . . . . 0 4—5
|         |
2 . . . . 1 . 0
              |
1 . . 2 1—0 . 0
|     | 
2 0—6 1 . . 3—5

DUPE

Duplicate the top item on the stack.

Stack Before	Stack After
[a, b]	[a, b, b]

ROLL

Pops one argument from the stack to be used as "depth".

• With a negative depth, the item at the top is moved to the nth depth
• With a positive depth, the item at the nth depth is moved to the top

With roll you can implement common stack operations like SWAP and ROT:

Roll Depth	Equivalent to	Stack Before	Stack After
-3	-	[a, b, c, d]	[d, a, b, c]
-2	ROTR	[a, b, c]	[c, a, b]
-1	SWAP	[a, b]	[b, a]
0	NOOP	[a]	[a]
1	SWAP	[a, b]	[b, a]
2	ROTL	[a, b, c]	[b, c, a]
3	-	[a, b, c, d]	[b, c, d, a]

LEN

Pushes the number of items on the stack.

CLR

Removes all items from the stack.

Arithmetic

ADD

Pops 2 numbers from the stack. The sum is pushed to the stack.

SUB

Pops 2 numbers from the stack. The result of numberA - numberB is pushed to the stack.

MULT

Pops 2 numbers to multiply. The result is pushed to the stack.

DIV

Pops 2 numbers. The result of the division of numberA by numberB is pushed to the stack.

Keep in mind that DominoScript is integer based and any remainder is discarded.

Pseudocode:

• NUM 5 NUM 3 DIV is 5 / 3 and equals 1
• NUM 5 NEG NUM 3 DIV is -5 / 3 and equals -1

MOD

Pops 2 numbers. The remainder of division of numberA / numberB is pushed to the stack.

Important

When numberA is positive modulo behaves identical in most languages (afaik). However, there are some differences across programming languages when numberA is negative. In DominoScript modulo behaves like in JavaScript, Java, C++ and Go and NOT like in Python or Ruby!

Pseudocode:

• NUM 5 NUM 3 MOD is 5 % 3 and equals 2
• NUM 5 NEG NUM 3 MOD is -5 % 3 and equals -2 (in python, ruby and calculators it would equal 1)

NEG

Pops the top item off the stack. Negates it. Then pushes the negated version back onto the stack. Essentially a num * -1 operation.

CLAMP

Pops 3 numbers from the stack:

[..., value, min, max]

And pushes back the clamped value onto the stack.

Comparison & Logical

NOT

Pops the top item off the stack. If it is 0, it pushes 1 to the stack. Otherwise it pushes 0.

AND

Pops the top 2 items off the stack, performs the logical AND operation and pushes the result back onto the stack.

OR

Pops the top 2 items off the stack, performs the logical OR operation and push the result back onto the stack.

EQL

Pops the top 2 items off the stack, compares them and pushes the result back onto the stack. If the items are equal, it pushes 1 to the stack, otherwise 0.

GTR

Pops the top 2 items off the stack, compares them and pushes the result back onto the stack. If the first item is greater than the second, it pushes 1 to the stack, otherwise 0.

EQLSTR

Assumes that 2 strings are on the stack. It pops them, compares them and pushes 1 to the stack if equal, otherwise 0.

For example:
You push the strings "AC" then "DC". They are represented on the stack as [NULL, C, A, NULL, C, D] (In reality it is [0, 67, 65, 0, 67, 68]). Since the strings are not equal, it will push 0 to the stack. It is now [0].

Another example:
Imagine you want to check if the user pressed arrow left. You execute the KEY instruction after which the stack looks like [<existing>, 0, 68, 91, 27] then you push the escape sequence which represents the left arrow key. The stack is now [<existing>, 0, 68, 91, 27, 0, 68, 91, 27]. You then execute the EQLSTR instruction which will pop the top 2 strings and since the strings are equal, it will push 1 to the stack. It is now [<existing>, 1] (See the KEY instruction for more info about escape sequences).

RESERVED_2_6

Unmapped opcode. Will throw InvalidInstructionError if executed.

Bitwise

BNOT

Bitwise NOT. Pops the top item off the stack, inverts all bits and pushes the result back onto the stack.

BAND

Bitwise AND. Pops the top 2 items off the stack, performs bitwise AND and pushes the result back onto the stack.

BOR

Bitwise OR. Pops the top 2 items off the stack, performs bitwise OR and pushes the result back onto the stack.

BXOR

Bitwise XOR. Pops the top 2 items off the stack, performs bitwise XOR and pushes the result back onto the stack.

LSL

Logical Shift Left. Performs the equivalent of argA << argB and pushes the result back onto the stack.

LSR

Logical Shift Right. Performs the equivalent of argA >>> argB and pushes the result back onto the stack.

ASR

Arithmetic Shift Right. Performs the equivalent of argA >> argB and pushes the result back onto the stack.

Control Flow

NAVM

Changes the Navigation Mode. The default Mode is 0.

See Navigation Modes to see all possible nav modes and their indexes.

BRANCH

Like an IF-ELSE statement.

It pops the top of the stack as a condition and then:

. . . . . 6 . .
          |
. . . . . 6 . .

0—1 0—1 4—1 . .
          
. . . . . 5 . .
          |
. . . . . 5 . .

• When popped value is true: The IP will move to the relative LEFT (the 6-6domino)
• When popped value is false: The IP will move to the relative RIGHT (the 5-5domino)

Important

It ignores the current Navigation Mode. You can always be assured that the IP will either move to the relative left or right.

Keep in mind that: all non-zero numbers are considered true. Only 0 is false! -1, -2 etc. ares all true (This fact might be obvious, but I felt like mentioning it as, when using ==, < or > for most conditions, it might be easy to forget).

LABEL

Label are like a bookmarks or an alternative identifier of a specific Cell address. They can be used by the JUMP, CALL, GET and SET instructions.

Labels are probably not what you expect them to be.

• They are not strings, but negative numbers.
• They are auto generated and self decrementing: -1, -2, -3, etc. ...
• You can kind of imagine them as pointers to a specific cell address.

Executing the LABEL instruction pops the address of the cell you want to label from the stack and assigns it to the next available negative number label.

The negative number label will NOT be pushed to the stack. First label will be -1, second label will be -2 and so on. You need to keep track of them yourself.

For clarity, I'd generally recommend adding comments like the following to your source files:

## Label Mappings
| Label | Address | Function name |
|-------|---------|---------------|
| -1    | 340     | main          |
| -2    | 675     | update        |
| -3    | 704     | whatever      |

It is not mandatory to use labels. The 4 mentioned instructions that can use them also work with addresses directly!

About Labels in imported files:
DominoScript has an IMPORT instruction that allows source files to be imported into others. The imported functions can only be called via labels, so in that regard a label also acts like an export. If the parent file doesn't define labels of their own, the label values will be the same in both parent and child. However if the parent file creates labels before importing a child file, the exported child labels will have a different value in the parent. For example:

1. Parent creates label -1, -2, -3 and then imports the child file
2. The child file defines labels -1, -2, -3 and gives back control to parent
3. The parent file will now have the labels -1, -2, -3 and the child labels will be -4, -5, -6
4. Now when the parent wants to call a child function which internally is labelled with -1, it needs to use label -4 instead.

JUMP

Moves the IP to an address on the grid. You can either use a label or an address as an argument.

If the IP cannot move anymore, the interpreter will throw a StepToEmptyCellError.

If label is unknown it will throw an UnknownLabelError.

CALL

Like the name suggests, it is similar to a function call.

Exactly like JUMP with one crucial difference: When it cannot move anymore, the IP will return to where it was called from instead of terminating the program.

Internally there is a return stack that keeps track of the return addresses.

Alternative way to CALL Instead of doing ǸUM 1 NEG CALL to call by label, you can just do OPCODE_100. Why? Because labels are mapped to opcodes 100+. So when you create the labels -1, -2, -3, etc. they are automatically mapped to opcodes 100, 101, 102.

Important

You can perform recursive calls (See factorial example) but be aware that the depth is limited by the size of the return stack. By default its size is 512.

IMPORT

Pop a "string" from the stack to indicate the file name of the source file to import.

On import the interpreter will load the file and start running it until its Instruction Pointer cannot move anymore.

Labels defined in the imported file are accessible from the file which imports it. That means you can call functions from the imported file via the CALL instruction.

If the importing file defined a label before the import, the labels from the imported file will have different identifiers. For example:

• FileChild.ds defines a label -1.
• FileAParent.ds defines labels -1, -2, then imports FileChilds.ds.s

The internal label -1 in FileChild.ds will be -3 externally in FileAParent.ds because labels are always auto decrementing. Why? Because it is the simplest way to avoid conflicts and be able to use labels internally and externally.

Important

The data stack is shared between parent and all imported files. Apart from that, the parent and child imports run in their own contexts. Imported files can have imports themselves but you should avoid circular dependencies.

If you import the same file into more than one other file, it will result in multiple instances of the imported file. This is probably not a problem as long as you are aware of it.

WAIT

Pops the top item off the stack and waits for that many milliseconds before continuing.

(You could simulate a delay without using WAIT using a 'busy loop' like in example 011_basic_game_loop but it is not recommended)

Input & Output

NUMIN

Prompt the user for a number. The user input will be pushed to the stack.

NUMOUT

Pop the top item from the stack and output it to stdout.

STRIN

Prompt the user for a string. The user input will be pushed to the stack as individual Unicode characters in reverse order.

So if the user inputs "yes", the stack will look like this:

[..., 0, 115, 101, 121]

For convenience you might often see the stack represented But remember that in reality it just stores int32s.

[..., NUL 's', 'e', 'y']

STROUT

Pops numbers (representing Unicode char codes) from the stack until it encounters a null terminator (number 0). It will then output the string to stdout.

There is one special case: If the parser encounters the Unit Separator (ascii 31), it stringifies the next number instead of treating it as a unicode char code. This is very useful to generate ANSI escape sequences like \x1b[15;20H[-] which tells the terminal to draw [-] at row 15 and column 20. Without the Unit Separator you would have to push the char code for 1, 5 and 2, 0 individually. This is a pain if you are dealing with dynamic numbers. The example_023 uses this to create an escape sequence.

KEY

Check if the user pressed a specific key since the last reset with KEYRES. If the key was pressed, it pushes 1 to the stack, otherwise 0.

It pops a string sequence of the stack to represent the key you want to check for.

Unlike NUMIN and STRIN it doesn't block the program, so you can use it in a loop to check for user input.

What string sequence?:

• If a key is a printable character, the sequence is the Unicode value of the key. For example, to check if the user pressed the a key, you would push the string a.
• If a key is a special key like arrow left, right etc, the sequence is an escape sequence. For example, to check if the user pressed the left arrow key, you would push the escape sequence \u001b[D to the stack.

What is an escape sequence?:

Escape sequences are sequences of characters that are used to represent special non-printable keyboard keys like arrow keys but can also be used to control terminal behavior, such as cursor position, text color and more. You can google them. Then just transform them to the correct domino sequence.

KEYRES

Resets the state of all keys to "not pressed". It is used in combination with KEY to check if a key was pressed since the last reset. It has no effect on the stack.

Imagine you have a game running at 20fps. Every 50ms you check if the user pressed any of the arrow keys and act accordingly. Then at the end of the frame you reset the state of all keys to "not pressed" with KEYRES.

RESERVED_5_6

Unmapped opcode. Will throw InvalidInstructionError if executed.

(Might be used as opcode for a MOUSE instruction which pushes the clickX and clickY position of the mouse since the last KEYRES reset)

Misc

GET

Reads data from the board and pushes it to the stack. Takes 2 arguments from the stack:

• The type Index to parse it as. It indicates the type and the direction of the data.
• The address of the first domino half

There are essentially 4 types you can parse it as:

• Domino: The value of the cell at the address and its connection. Essentially a single domino
• Unsigned Number: A number between 0 to 2147483647 (Hold on! Why not 4294967295? Because the data stack uses int32 and 2147483647 is the max value you can have in the stack. "Unsigned" here doesn't mean uint32, just that we don't "waste" half a domino to represent the sign).
• Signed Number: A number between -2147483648 to 2147483647 (int32 range).
• String: A string is a sequence of null terminated unicode char codes.

And the following directions:

• SingleStraightLine: The IP moves in a straight line towards the connection direction of the cell at the address. No wrap around like in "RawIncrement" mode. If you have a 10x20 grid you can get at most 5 dominos in horizontal direction or 10 dominos in vertical direction.

• RawIncrement (to be implemented): Reads domino halfs using incrementing addresses. It disregards the grids bounds and wraps around from right edge left edge on the next line (Remember that addresses are essentially the indices to a 1D array of Cells which represent the Grid. Address 0 is at the top left of the grid. In a 10x10 grid, the largest address is 99 in the bottom right)

• NavMode (to be implemented): In this mode the NavigationMode used for regular InstructionPointer movement is used to determine the direction.

Here a table of supported type mappings:

Type Index	Type	Direction
0	Domino	connection direction
1	Unsigned Number	SingleStraightLine
2	Signed Number	SingleStraightLine
3	String	SingleStraightLine
4 (TODO)	Unsigned Number	RawIncrement
5 (TODO)	Signed Number	RawIncrement
6 (TODO)	String	RawIncrement

SET

Writes data to the board. Takes at least 2 arguments from the stack:

• The type Index to parse it as. It indicates the type and the direction of the data
• The address of the first domino half
• The data to write to the board. This can either be a single item from the stack or multiple if we write a string

There are essentially 4 types you can write it as

(See list under GET):

And the following directions:

• SingleStraightLine: The IP moves in a straight line towards the last Instruction Pointer direction. No wrap around like in "RawIncrement" mode. If you have a 10x20 grid you can set at most 5 dominos in horizontal direction or 10 dominos in vertical direction.

• RawIncrement (to be implemented): Writes domino halfs using incrementing addresses. It disregards the grids bounds and wraps around from right edge left edge on the next line (Remember that addresses are essentially the indices to a 1D array of Cells which represent the Grid. Address 0 is at the top left of the grid. In a 10x10 grid, the largest address is 99 in the bottom right)

• NavMode (to be implemented): In this mode the NavigationMode used for regular InstructionPointer movement is used to determine the direction.

Here a table of supported type mappings:

(See table under GET):

LIT

Changes how number and string literals are parsed. It pops a number from the stack to use as the "literal parse mode". The popped number must be between 0 to 6. If the number is out of bounds, an DSInvalidLiteralParseModeError is thrown.

If the popped argument is:

• 0: Dynamic parse mode. Used by default. The first domino half of every number literal indicates how many more dominos should be parsed as part of the number. For string literals it is exactly the same but for each character.
• 1 to 6: Static parse modes. Uses 1 to 6 dominos for each number literal or each character in a string literal.

In the following 3 examples "Hello world" is encoded in 3 different ways:

In Base7 with Literal Parse Mode 0 (default):

// Every character requires 2 dominos to be encoded on dominos
0—2 1—2 0—6 1—2 0—3 1—2 1—3 1—2 1—3 1—2 1—6 1—0 4—4 1—2 3—0 1—2 1—6 1—2 2—2 1—2 1—3 1—2 0—2 0—0

In Base 16 with Literal Parse Mode 0:

// Still every character requires 2 dominos to be encoded. Considering that we are in base 16, very wasteful!
0—2 1—0 6—8 1—0 6—5 1—0 6—c 1—0 6—c 1—0 6—f 1—0 2—0 1—0 7—7 1—0 6—f 1—0 7—2 1—0 6—c 1—0 6—4 0—0

In Base 16 with Literal Parse Mode 1:

// Every character requires 1 domino to be encoded.
// Notice how now it is pretty much just hexadecimal
0—2 6—8 6—5 6—c 6—c 6—f 2—0 7—7 6—f 7—2 6—c 6—4 0—0

As you can see, changing the default parse mode can significantly reduce the amount of dominos required to encode strings. For numbers it is less impactful but can still be significant if you are working mostly within a specific range.

BASE

Pops one number from the stack to use as the "base" for future parsing of dominos (opcodes, number literals, string literals)

By default, DominoScript uses double six (D6) dominos to represent everything, so the default base is 7.

The max cell value of half of a domino is always 1 less than the Base. So in base 7, the max value is 6. In base 10, the max value is 9. In base 16, the max value is 15 (aka f).

Important

If the number of dots on a domino half exceeds the max amount of possible dots for the current base, it is clamped!

For example: when you are in Base 7 and the interpreter encounters a f—f domino, it will be parsed as 6—6. If you are in base 10, it will be parsed as 9—9 etc.

In below table you can see how the same domino sequence results in different decimal numbers depending on the base:

Domino Sequence	Base 7 (D6)	Base 10 (D9)	Base 16 (D15)
0—6	6	6	6
0—9	6	9	9
0—f	6	9	15
1—6 6—6	342	666	1638
1—9 9—9	342	999	2457
1—f f—f	342	999	4095
2—6 6—6 6—6	16806	66666	419430
2—9 9—9 9—9	16806	99999	629145
2—f f—f f—f	16806	99999	1048575

With a higher Base, you have access to higher opcodes without needing to switch to extended mode.

Base	Opcode Range
7	0 to 48
10	0 to 99
16	0 to 255

While the opcode-to-instruction mapping never changes, the domino-to-opcode mapping is completely different in each base.

The below table shows how the domino 3—0 is mapped to different opcodes depending on the base.

Base	Opcode	Instruction
7	21	BNOT
8	24	BOR
9	27	LSL
10	30	BRANCH
11	33	IMPORT
12	36	NUMIN
13	39	undefined
14	42	GET
15	45	BASE
16	48	NOOP

EXT

Toggle extended mode on or off. If extended mode is active the interpreter will use 2 dominos instead of 1 for each instruction which extends the opcode range from 0-48 to 0-2400 when using Double six dominos.

TIME

Pushes the milliseconds since program start to the stack.

Useful for things like a gameloop, animations, cooldowns etc.

NOOP

No operation. The IP will move to the next domino without doing anything.

Useful to move the IP to a specific address (e.g. start of loop body) or to "reserve" space in case you think that you might need to add more instructions later on and don't want to move dominos around.

Navigation Modes

(F=Forward, L=Left, R=Right)

There are 49 total navigation modes in DominoScript. This section is a reference for all of them.

• Basic: The IP will prioritize moving in specific directions
  • Basic Three Way
  • Basic Two Way
  • Basic One Way
• Cycle: The IP will prioritize moving in specific directions but the priority will change every cycle.
  • Cycle Three Way
  • Cycle Two Way
  • Cycle One Way
• Flip Flop: The IP will alternate between two primary directions.
  • Flip Flop

Basic Three Way

Out of three directions, the IP will prioritize moving to the one with the highest priority.

Index	Priorities	Domino ->
0 (Default)	Forward Left Right	0—0
1	Forward Right Left	0—1
2	Left Forward Right	0—2
3	Left Right Forward	0—3
4	Right Forward Left	0—4
5	Right Left Forward	0—5
6	RANDOM	0—6

Basic Two Way

Out of two directions, the IP will prioritize moving to the one with the highest priority.

Index	Priorities	Domino ->
7	Forward Left	1—0
8	Forward Right	1—1
9	Left Forward	1—2
10	Left Right	1—3
11	Right Forward	1—4
12	Right Left	1—5
13	RANDOM	1—6

Basic One Way

IP can only move in one direction.

Index	Only Direction	Domino ->
14	Forward	2—0
15	Forward	2—1
16	Left	2—2
17	Left	2—3
18	Right	2—4
19	Right	2—5
20	RANDOM	2—6

Cycle Three Way

The direction with the highest priority becomes the least prioritized in the next cycle.

All 3 directions are available in all cycles.

Index	Cycle 1	Cycle 2	Cycle 3	Domino ->
21	F L R	L R F	R F L	3—0
22	F R L	R F F	L F R	3—1
23	L F R	F R F	R L F	3—2
24	L R F	R F L	F L R	3—3
25	R F L	F L R	L R F	3—4
26	R L F	L F R	F R L	3—5
27	(unmapped)	(unmapped)	(unmapped)	3—6

Cycle Two Way

The direction with the highest priority becomes the least prioritized in the next cycle.

Only 2 directions are available in a single cycle.

Index	Cycle 1	Cycle 2	Cycle 3	Domino ->
28	F L	L R	R F	4—0
29	F R	R F	L F	4—1
30	L F	F R	R L	4—2
31	L R	R F	F L	4—3
32	R F	F L	L R	4—4
33	R L	L F	F R	4—5
34	(unmapped)	(unmapped)	(unmapped)	4—6

Cycle One Way

The direction with the highest priority becomes the least prioritized in the next cycle.

Only 1 direction is available in a single cycle.

Index	Cycle 1	Cycle 2	Cycle 3	Domino ->
35	F	L	R	5—0
36	F	R	L	5—1
37	L	F	R	5—2
38	L	R	F	5—3
39	R	F	L	5—4
40	R	L	F	5—5
41	(unmapped)	(unmapped)	(unmapped)	5—6

Flip Flop

The priority flip flops between 2 primary directions.

Index	Flip	Flop	Domino ->
42	F	L	6—0
43	F	R	6—1
44	L	F	6—2
45	L	R	6—3
46	R	F	6—4
47	R	L	6—5
48	(unmapped)	(unmapped)	6—6

Error Types

The spec doesn't define a way to recover from errors gracefully yet. For now, whenever an error occurs, the program will terminate immediately and the interpreter will print the error message to the console in an attempt to help you understand what went wrong.

Tip

If the error message isn't helpful to you, try using the --debug flag when using the reference interpreter. This will print out every instruction, address and the state of the stack at any point in time.

Here is a list of errors that can occur:

• InterpreterError: Something wrong with the Interpreter: {message}
• SyntaxError: Unexpected token '{token}' at line {line}, column {column}
• InvalidGridError: Invalid grid. All lines containing code must be the same length (for now)
• MultiConnectionError: {type} connection at line {line}, column {column} is trying to connect a cell that is already connected
• MissingConnectionError: Non-empty cell at line {line}, column {column} does not have a connection
• ConnectionToEmptyCellError: Connection to an empty cell at line {line}, column {column}
• ConnectionToEmptyCellsError: There are connectors that are not connected to anything (Cannot give you the exact location of the error atm)
• UnexpectedEndOfInputError: Unexpected end of input at line {line}, column {column}
• AddressError: Address '{address}' out of bounds
• InvalidLabelError: Label {name} is not a valid label
• StepToEmptyCellError: Trying to step from cell {currentAddress} to empty cell {emptyAddress}
• JumpToItselfError: Jumping to itself at address {address} is forbidden as it results in an infinite loop
• JumpToExternalLabelError: Jumping to an external label from {name} at address {address} is forbidden. External labels can only be used by CALL instruction
• CallToItselfError:Calling to itself at address {address} is forbidden as it results in an infinite loop
• UnexpectedEndOfNumberError: Unexpected end of number at address {address}
• ValueTooLargeError: The value {value} is too large. Currently LIT {literalParseMode} is set. Meaning each number must fit on {literalParseMode} domino(s). Try increasing the LIT or use a higher BASE`.
• UnexpectedChangeInDirectionError: Unexpected change in direction at address {address}. When using GET or SET the direction is dictated by the first domino and cannot change
• EmptyStackError: Cannot pop from an empty stack
• FullStackError: Cannot push to a full stack
• InvalidInstructionError: Invalid instruction opcode {opcode}
• InvalidNavigationModeError: Invalid navigation mode {mode}
• InvalidValueError: Invalid value {value}
• InvalidSignError: Invalid sign {value} at address {address}. When getting a signed number, the sign cell must be either 0 (pos) or 1 (neg)
• DSInvalidBaseError: Invalid base {base}. You can only set the base to a number between 7 and 16
• DSInvalidLiteralParseModeError: Invalid literal parse mode {value}. You can only set the parse mode to a number between 0 and 6
• InvalidInputError: Invalid input {reason}
• MissingListenerError: NUMIN, NUMOUT, STRIN or STROUT instructions were called and the DominoScript "runtime" did not provide a way on how to handle input or output

Contributing

Do you have any feature suggestions? Do you have any questions? Have you written any code in DominoScript and would like to share it? - Feel free to open issues and start discussions in this repo!

I am grateful for any interest and help in finding bugs, fixing spelling errors and improving the documentation. If you create any programs or use DominoScript in any way, please let me know. I would love to see what you come up with!

This silly language is still in its early stages but most of the "core" features have already been implemented. I am very hesitant to introduce breaking changes but until the release of v1.0.0 there might still be some.

See the roadmap for ideas.

If you are curious, see my Notes to learn about the thought process that went into making DominoScript.

Roadmap

Not sure if the term "roadmap" is appropriate. This is more of a list of things that I would like to see implemented:

• More instructions for fixed point arithmetic, string manipulations, networking, syscalls etc. could be useful (in theory DS can support up to 1000 opcodes. Only ~47 are used at the moment)
• More Navigation Modes The nav mode decides where the Instruction Pointer will move to next. We already have quite a lot of nav modes. Most of which are just variations of each other. Currently the IP can only move in cardinal directons to direct neighbours. New nav modes might introduce diagonal movement, or allow the IP to move to non-direct neighbours etc.
• Better Documentation that is more concise and better structured. A short tutorial would be useful to familiarize new users with the language. Maybe on its own website with interactive snippets.
• More Interpreters Once I am happy with the core functionality, I want to create at least 1-2 more reference interpreters in different languages. Probably in C and/or Go.
• A Simple CLI Game like Snake or Breakout. When I started designing the language my goal was to eventually create a pong-like game with it.
• A brainf"ck interpreter written in DominoScript.
• Interactive online playground where you can write and run DominoScript code in the browser. Maybe allow users to share their code and let others rate it.
• A minimal game engine written in a sane language that uses DominoScript as its primary scripting language.
• A Compiler. Probably not an easy task given the self-modifying 2D nature of the language and its NavModes. Maybe some form of JIT compilation for frequently used paths or special instructions indicating "compile-safe-mode".
• A Scanner that can read DominoScript from images of real Domino pieces like a QR code scanner (minus the redundancy and error correction). It could probably work fairly reliably with a good enough camera and a limited grid size.

Examples

A list of examples to help you understand the language better.

1. Hello World minimal
2. Hello World Commented
3. Hello World 2D
4. Loop Simple
5. Loop using jump
6. Loop using jump and label
7. Call function by address
8. Call function by label
9. Recursion: Factorial
10. Navigation Mode changes
11. Basic game loop
12. Number Input
13. String Input
14. Import script into another
15. Call imported function
16. Ansi clear screen
17. Using delay
18. Reverse String
19. Input Controls
20. Check String Equality
21. Reduce domino amount
22. Modify Code using SET
23. WASD Controls
24. Benchmark 01

If you want your example to be added to this list, please create a PR.