This repository is a POC, test stack based VM, and accompanying programming language, with a compiler. The purpose of this project is not to create a real-world usable programming language and VM, but merely for educaitonal purposes, and fun!

The Virtual Machine is written in C. For simplicity it only has 3 fundamental data types:

1. ints (8/32/64 bit integers)
2. floats (32/64 bit floats)
3. strings

as well as 4. arrays, of homogeneous data items. (e.g. an int array, float array etc) 5. records, similar to C structs.

The VM reads bytecode and runs the encoded instructions. A single stack is used, along with a few registers.

Note the tachyon virtual machine executable is assumed located in the ./virtual_machine/build directory, which is the location it is put when compiled.

./build/tachyon -s 600 -h 1000 -p ../compiler/output/countdown.btyarc -d 1

-s is the max stack size, in "cells", which are 4 bytes.

-h is the max heap size in bytes (unused), waiting for a custom allocator.

-p is path to the file to be run in the VM.

-d is debugging flag. If 1, then some debug output will be displayed. If 0 then no debug output.

The Tachyon programming language ius a simple language, that compiles into the Tachyon VM bytecode.

The compiler is written in Python, and uses the Lark library for parsing the Tachyon .ty files and then compiles the code into tachyon bytecode. The result is a btyarc file, which can be read by the tachyon virtual machine.

The parser and compiler are written in Python. The Parser uses Lark to aprse the grammar for the toy Tachyon language.

python main.py --program /path/to/source.ty -v 1

function main() -> i32 {
 ...
 return 1;
}

main();

The main datatypes are

1. i8, i32, i64 : 8,32,64-bit signed integers.
2. f32, f64: 32,64-bit floating point numbers.
3. str: Strings, delimited by the ' (single quote) character, not double quotes (").

The other datatypes are

1. arrays
2. records

Array size must be given at compile time. Array items must all have the same type. Records are similar to C structs. They can hold different item types.

All variables are passed by value and there are no pointers or references, limiting the language somewhat.

arr : i8[10] = [1,2,3,4,5,6,7,8,9,10];

record vector (
 x : f32,
 y : f32,
 z : f32
);

a : vector = rec vector(0.0,0.0,0.0);

function xyz(var1 : i32, var2 : i32) -> f32 {

    f : f32 = 0.0;
    f = (!f32!var1) + (!f32!var2);
    return f;
}

function main() ->i32 {
    f : f32 = xyz(1,10);
    print(f);
    return 1;
}

main();