tslox

The Repository

tslox is an interpreter of Lox language written entirely in TypeScript.

Lox is a scripting language created by Robert Nystrom for Crafting Interpreters book. tslox is the Tree-Walk Interpreter implemented in TypeScript.

Status

• Main parts implemented
• Challenges
• Personally interested features

Lox differences and challenges

Some differences to basic Lox implemented in the book

Array

Check test file for more detail

var n = 10 ;
var fib = [0, 1] ;

for(var i = 2; i < 20; i = i + 1){
    fib[i] = fib[ i-1 ] + fib[ i-2 ] ;
}
print fib ; // [ 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181 ]
print fib.length ; // 20

Ternary operator

Chapter 6, Challenge 2

    print 5 > 3 ? "yes" : "no" ; // "yes"

lambda

Chapter 10, Challenge 2

    fun thrice(fn) {
        for (var i = 1; i <= 3; i = i + 1) {
            fn(i);
        }
    }

    thrice(fun (a) {
        print a ;
    });

Usage

Install dependencies

$ yarn

Running File

$ yarn lox <file name>

For example

$ yarn lox ex/helloWorld.lox
Hello world!

Running REPL

$ yarn lox

For example

$ yarn lox
[lox]: var cookie = 5 ;
[lox]: print cookie ;
5
[lox]: Bye! # cmd + c to exit

Running Test

yarn test # immediately in watch mode