Threes is a novelty programming language that operates as a stack-based reduced instruction set language.
All source code written in Threes are written using only the following characters: 0, 1, 2, and 3.
Example: the following code prints "Hello, World!" to the console
321201
3211210
3211230
3211302
3211233
3211313
321200
321230
3211233
3211230
3211230
3211211
3211020
32131
23
30
1111
22
21133
Takes the top two values on the stack and pushes their sum to the stack.
Takes the top value from the stack and pushes back the result of adding the provided immediate.
Takes the top two values on the stack and pushes their difference (top minus second from the second-from-the-top) to the stack.
Takes the top value from the stack and pushes back the result of subtracting the provided immediate.
Takes the top two values on the stack and pushes their product to the stack.
Takes the top value from the stack and pushes back the result of multiplying by the provided immediate.
Takes the top two values on the stack and pushes their quotient (top minus divided by the second-from-the-top) to the stack.
Takes the top value from the stack and pushes back the result of dividing by the provided immediate.
Pops the top value from the stack and prints it as a number
Pops the top value from the stack and prints it as a character.
Jumps to the provided line number if the stack contains a value, and it is non-zero
Jumps to the provided line number if the stack is empty or the top value is a zero.
Duplicates the top value in the stack
Swaps the top values in the stack. Optionally takes a provided line count, which informs the command how many lines to swap (default two).
Loads the provided immediate value to the top of the stack
Anything following this command is treated as a comment and is ignored by the interpreter (yes, even normal words 😱)
Immediates, or integer literals, are encoded as a positive base 4 value with a numeric prefix indicating sign where positive values start with odd prefixes while negative values start with even prefixes. The same rules apply for characters. If a character were to be encoded as an immediate, then the ascii value would be converted to base 4 and then prefixed with an odd number (e.g., 'A' becomes 11000).
Examples:
| Decimal Number | Base 4 | Immediate Encoding |
|---|---|---|
| 1 | 1 | 11 |
| -1 | -1 | 21 |
| -1 | -1 | 21 |
| 16 | 100 | 3100 |