Rlox

Rlox is a rust implementation of the lox language, which is a simple and concise dynamically typed script language designed by Robert Nystrom in his book Crafting Interpreters. This repository now contains only a tree-walker interpreter for lox.

Note. Rlox isn't a faithful implementation to the standard specified from the book. I did some little changes based on my own appetite, such as removing inheritance (partly because of my laziness) and adding support for arrays. But other parts are almost the same.

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To start up a repl, just type

rlox

To run a lox script, type

rlox [script]

If the interpreter happened to encounter some errors, hopefully it will point out the problem and cease executing.

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Here is an overview of rlox.

var a = 1;
var array = [32768, "halo", [4,2]];
var a = "Number " + a; // variable shadowing
var length = len(array);
for (var i = 0; i < length; i = i + 1) { // classic C-styled for loop
    array = array + array[i]; // print is embedded into the language
}
for e in array { // or you can use a for-in loop
    print typeof(e); // rlox has 7 types: number, string, boolean, function, class, instance, array
}
while true {
    break; // rlox supports basic control flow statements: break, continue, return
}
fun add(a, b) {
    return a + b;
}
fun get_callback(n) {
    var base = n;
    return |y| base + y; // rlox supports closure and rust-like lambda expressions.
    					 // or you can write |y| { return base + y; }
}
var closure = get_callback(43);
print closure(-1);

class Block {
    init(width, height) {
        this.width = width;
        this.height = height;
    }
    square() {
        return this.width * this.height;
    }
}

var block = Block();
block.init(3,4);
print block.square();