An esoteric programming language with prefix-free brackets
tru is an esoteric programming language of brackets with prefix-free code.
Below are some tru code examples.
# print hello world
(0)(10)(33)(100)(108)(114)(111)(119)(32)(44)(111)(108)(108)(101)(72)>><<[<><>><<>><<]>>><<
# print 25th Fibonacci number
(1)(25)(1)><>(1)(0)><>(1)>>>>>><<[(0)><>(1)>>>>>><<[>><>(1)><>>><<(0)><>>>><>(1)><><<<>><>>>><>(0)><>>><>(1)>>>>>><<](0)](1)><><><>><>>>><<
# sum first 1000 positive integers
(1000)>><<>>><>(1)><>1(111)[(1)>>>>1>><<>>><>(0)><>0<<<(1)><>1>><<(1)<>>><<](0)><><><>><>>>><<
# quine (outputs its own source code)
(9999)(60)(60)(62)(62)(62)(60)(60)(62)(60)(93)(60)(60)(62)(62)(62)(60)(60)(60)(60)(41)(1)(40)(41)(9998)(40)(60)(60)(62)(62)(93)(41)(0)(40)(62)(60)(62)(41)(0)(40)(41)(7777)(40)(62)(60)(62)(41)(1)(40)(60)(60)(62)(62)(60)(62)(60)(62)(60)(62)(62)(62)(60)(60)(62)(62)(62)(60)(62)(41)(0)(40)(91)(60)(60)(62)(62)(60)(62)(41)(1)(40)(93)(41)(0)(40)(62)(60)(62)(41)(0)(40)(41)(8888)(40)(62)(60)(62)(41)(1)(40)(62)(60)(62)(62)(60)(62)(60)(62)(60)(62)(62)(62)(60)(60)(62)(62)(62)(60)(62)(41)(0)(40)(91)(60)(60)(62)(62)(62)(62)(60)(41)(2)(40)(62)(60)(62)(41)(1)(40)(62)(60)(62)(62)(62)(60)(60)(60)(62)(60)(62)(41)(0)(40)(62)(60)(62)(62)(62)(62)(62)(60)(41)(40)(40)(60)(60)(62)(62)(62)(60)(62)(62)(62)(62)(62)(60)(41)(7777)(40)(62)(60)(62)(41)(1)(40)(91)(41)(1)(40)(41)(1)(40)(41)(8888)(40)(62)(60)(62)(41)(1)(40)(60)(60)(62)(60)(93)(93)(41)(0)(40)(60)(60)(62)(62)(60)(62)(60)(41)(41)(40)(62)(60)(62)(62)(60)(62)(60)(62)(60)(62)(62)(62)(60)(60)(62)(62)(60)(60)(62)(62)(60)(62)(60)(41)(40)(40)(62)(60)(62)(62)(91)(60)(60)(62)(62)(60)(60)(62)(62)(62)(60)(60)(60)(60)(41)(1)(40)(41)(9998)(40)(60)(60)(62)(62)(62)(60)(62)(41)(1)(40)(91)(41)(1)(40)(60)(60)(60)(41)(1)(40)(41)(9998)(40)(62)(60)(62)(41)(0)(40)(60)(60)(62)(62)(60)(62)(60)(41)(41)(40)(62)(60)(62)(62)(60)(62)(60)(60)(60)(60)(41)(1)(40)(41)(9998)(40)(60)(60)(62)(62)(60)(62)(60)(41)(40)(40)(60)(60)(62)(60)(93)(93)(41)(0)(40)(62)(60)(62)(62)(62)(62)(60)(62)(62)(91)(60)(60)(62)(62)(60)(60)(62)(62)(62)(60)(60)(60)(60)(41)(1)(40)(41)(9998)(40)(60)(60)(62)(62)(62)(60)(62)(41)(0)(40)(91)(41)(1)(40)(60)(60)(60)(41)(1)(40)(41)(9998)(40)(62)(60)(62)(41)(1)(40)(1)><>(9998)(1)<<<(1)[(0)><>>><<(9998)(1)<<<<>>><<>><<[>><>>>><>(0)]]<><<(40)<><>><<(9998)(1)<<<<><>><>(41)<><>><<(0)><>(9998)(1)<<<(1)[(1)><>>><<(9998)(1)<<<<>>><<>><<[>><>(40)<><>><<>><<>>><><><>><>(41)<><>><<(0)]]<><<(1)><>(8888)(1)(1)[(1)><>(7777)<>>>>><>>><<(40)<>>>>><>(0)><><<<>>><>(1)><>(2)<>>>><<[(0)><>>><<>>><><><>><>(1)><>(8888)(0)><>(0)](1)><>><<[(0)><>>><<>>><><><>><<(1)><>(7777)(0)><>(0)]>><<(9998)(1)<<<<>>><<]<><<>>><<
Tru is a stack-based virtual machine.
There are two built-in stacks which tru programs can manipulate using the following set of instructions.
| Instruction | Description |
|---|---|
( |
Start describing an integer to push |
) |
Push the integer between the corresponding opening bracket to the current stack. |
<><>><< |
Print character: Pop from the current stack and print the value as a UTF-8 character |
<><>><> |
Print integer: Pop from the current stack and print the value as a number |
<><>>> |
Integer input: Get an integer input and push to the current stack as a number |
<><>< |
Character input: Get an integer input and push to the current stack as a UTF-8 character |
>>><< |
End: Specify the end of the program |
>>><> |
Move: Pop from the current stack and push to the other stack |
<><< |
Discard: Pop from the current stack and discard |
>><< |
Duplicate the top value of the current stack |
>><> |
Swap the top two values of the current stack |
>>>> |
Subtract |
<<< |
Add |
<<> |
Greater than |
<>> |
Equals |
><< |
Not |
><> |
Select stack: Pop from the stack and set the current stack equal to the value. The stacks are indexed 0 and 1. |
[ |
Jump: Pop the current stack and jump to the matching ] if the value is zero |
] |
Jump: Pop the current stack and jump to the matching [ if the value is non-zero |
# |
Comment: ignore all characters that follow for the rest of the line |
In summary, instructions are represented by only using bracket characters:
(, ), [, ], <, >
Instructions are prefix-free and can directly follow one another. For instance,
(1)
>><<
(2)
<<<
>><<
<><>><<
is equivalent to
(1)>><<(2)<<<>><<<><>><<
Linebreaks and spaces are permitted and ignored. However, numbers and instructions cannot be broken with linebreaks or spaces.
# Okay
(
10
)
# Not okay
(
1
0
)
# Okay
>><<
# Not okay
>>
<<
One can write a relatively readable tru program using linebreaks, spaces and comments. It can always be compressed due to the prefix-free nature of the instructions.
Pytru is an official tru virtual machine implemented in Python. You can use it to execute tru code.
# pytru requires Python 3
python3 ./tru.py input_file_path
Apache 2.0