pjscript 0.0.4

JS like simple language LEXER, PARSER and INTERPRETER

A single file, dependency free language written in python. The goal of this project is to show that programming languages are not a black box and that you could learn the basic concpets required to implement your own language. While this language is not a real programming language however a lot of the internal concepts displayed in this language is taken from other real programming languages.

how to Run

python -m pjscript <file.js>

#or you could use the lexer, parser and interpreter in your python file

from pjcript import *

lexer = Lexer("var x = 1;")
tree = Parser(lexer)
interpreter = Interpreter(tree)
interpreter.interpret()

Data types:

- Int (positive & negitive)
- String
- Array
- Object
- Null

Basic statemnets

/* this is a comment */
var age = 2;
var name = "jack";
var newage = age;
name = "jack and me";
log(1, "it's working fuck yea", name);
var x = add(age, add(2,3));
log(x);

Functions and Scope

var x = "hello world";

function printme(st1, st2, st3){
    log(st1);
    log(st2);
    log(st3);
};

function testfunc(){
    var x = "new thing";
    printme(x, 1, 3);
};

testfunc();
log(x);

Expressions

var x = 0 + add(2, 3);
var x = x + add(2, 3);
var x = (x * 2) / 2;
log(x); /* should log 10*/

function Mul(){
    return add(2, add(2 * 3, 2));
};

var result = Mul();
log(result);


/* post-increment and decrement */
var x = 2;
log("x: ", x);

var y = x++ * 2;
log("y: ", y); /* output y: 4 */
log("x: ", x); /* output y: 3 */

/* pre-increment and decrement */
var x = 2;
log("x: ", x);

var y = ++x * 2;
log("y: ", y);/* output y: 6 */
log("x: ", x);/* output y: 3 */


/* Comparison Operators */

var x = 2;
var y = x >= 2;
log("y: ", y); /* True */
log("x: ", x); /* 2 */

For Loops

for(var i = 0; i < 5; i++){
    log(i);
};

/* or */
var i = 0;
for(i = 2; i < 5; i++){
    log(i);
};

/* infinite loop */
var i = 0;
for(; ; i++){
    log(i);
};

IF ELSE

var x = 0;
if(x == 3){
    log("if");

} else if(x == 2){
    log("else if");

} else if (x == 1){
    log("else if second");

}else{
    log("else");
};

var y = 2;
if (x == 2){
    log("if only");
};

for(var i = 0; i < 5; i++){
    if(i == 3){
        log(i);
    };
};

Array

// numbers
var numbers = [1, 2, 3];
log(numbers);
log(numbers[2]);


// Strings
var person = ["jack", "jay", "nick"];
for(var i = 0; i < 3; i++){
    log(person[i]);
};

Object

// Object
var person = {
    name: "jack",
    age: 23
};

log(person.name);
log(person.age);