Loxi

Bytecode interpreter for the Lox language with a mark and sweep garbage collector, based on the second half of Crafting Interpreters by Robert Nystorm.

You can use the WASM playground hosted on GitHub Pages.

Lists

Also supports lists and has additional native functions. Credits to Caleb Schoepp's blog.

var l = [1, 2, 3, 4, 5];
print "List";
print l; // [1, 2, 3, 4, 5]

print "Append";
append(l, 6);
print l; // [1, 2, 3, 4, 5, 6];

print "Insert";
insert(l, 0, -1);
print l; // [-1, 1, 2, 3, 4, 5, 6];

print "Pop";
print pop(l); // 6

print "Delete";
delete(l, 0);
print l; // [1, 2, 3, 4, 5];

fun reverse(l) {
    var n = len(l); // also works on strings

    for (var i = 0; i < n / 2; i = i + 1) {
        var tmp = l[i];
        l[i] = l[n - 1 - i];
        l[n - 1 - i] = tmp;
    }
}

print "Reversed";
reverse(l);
print l; // [5, 4, 3, 2, 1];

var x = list(0, 5); 
print x; // [0, 0, 0, 0, 0]
x[1] = "hello";
x[2] = reverse;
x[3] = "world";
print x; // [0, hello, <fn reverse>, world, 0]
x[2](x); // [0, world, <fn reverse>, hello, 0]
print x;

var fib = [0, 1]; 
for (var i=0; i<15; i=i+1) append(fib, fib[-1] + fib[-2]);

print "Fibonacci numbers";
print fib; // [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987]

Note

Flags

Use the Odin compiler's optimization flags, such as -o:speed flag on the below commands.
For NaN boxing, you can use the flag -define:NAN_BOXING=true on the below commands.
You can use the debug flags -define:PRINT_CODE=true, -define:TRACE_EXECUTION=true and -define:LOG_GC=true.

Build and run

# repl
odin run loxi

# file
odin run loxi -- <filepath>

Build

odin build loxi

Run

# repl
./loxi.bin # unix

.\loxi.exe # windows

# file
./loxi.bin <filepath> # unix

.\loxi.exe <filepath> # windows

WASM

git switch wasm
odin build ./loxi -target:js_wasm32 -out:./docs/loxi.wasm -no-entry-point -o:speed
miniserve ./docs --index ./docs/index.html