Zealot

Zealot is a Dynamically typed Tree-Walking Interpreter designed for simplicity, efficiency, and ease of use.

Why

Zealot is designed to provide a clean and concise syntax while being powerful and easy to learn.

Prerequisites

• Java Development Kit (JDK)
• Make (Optional)

Installation

1. Clone Zealot official repository:

git clone https://github.com/kmr-ankitt/Zealot.git
cd Zealot

2. Install Zealot:

source .bashrc  # For Linux/macOS

3. Run Zealot REPL:

zealot

You can also run Zealot using Makefile:

make compile
make repl

4. Run .zlt file:

zealot FILE_DIRECTORY/FILE_NAME.zlt

Or using Makefile:

make run INPUT="FILE_DIRECTORY/FILE_NAME.zlt"

Zealot Documentation

File extension

Zealot supports only .zlt file extension. example: main.zlt

Hello, world!

A simple hello world program in Zealot:

print "Hello, World!";

Semi-colons at the end of every line are mandatory in Zealot.

Datatypes

Zealot has the following datatypes:

Numbers

Number literals can be both integers and floating-point numbers.

examples: 1, 2.5, 9

Strings

String literals are defined inside ".

examples: "Zealot", "Strings are easy"

Booleans

Boolean literals can be either true or false.

examples: true, false

Null Type

Zealot has a null datatype. It can be defined using the nill keyword. All uninitialized variables are given the value of nill.

examples: nill

Operators

Zealot has the following operators:

Assignment

= - equals

Unary operators

- - Unary negation

Logical operators

and - logical AND

or - logical OR

! - logical NOT

Arithmetic operators

+ - sum

- - difference

* - product

/ - division

% - mod

Comparison operators

== - is equals

!= - is not equals

< - is less than

<= - is less than or equals

> - is greater than

>= - is greater than or equals

Comments

Zealot supports both single-line and multi-line comments.

• Single-line comment

// This is a single-line comment.

• Multi-line comment

/*This is a multi-line comment in Zealot.*/

Variables

var num = 15; // number
var name = "radiohead"; // string
var truth = true; // boolean
var lie = false; // boolean
var nullable = nill; // null type

Logical operators

!true;  // false.
!false; // true.
true and false; // false.
true and true;  // true.
false or false; // false.
true or false;  // true.

Control flow

var num = 15;

if(num > 0){
    print "num is positive";
}else {
    print "num is negative";
}

Loops

for(var i = 0; i < 10; i = i + 1){
    print i;
}

var num = 1;
while(num > 0){
    print num;
    num = num - 1;
}

Functions

fun add(a, b){
    return a + b;
}

print add(5, 10);

Closures

fun addPair(a, b) {
    return a + b;
}

fun identity(a) {
    return a;
}

print identity(addPair)(1, 2); // Prints "3".

fun makeCounter(){
    var c = 0;
    fun counter(){
        c = c + 1;
        print c;
    }
    return counter;
}

var counter1 = makeCounter();
var counter2 = makeCounter();

counter1(); // 1
counter2(); // 1

Classes

Zealot supports object-oriented programming with classes.

• Keywords: class for defining a class, this for the current context.

class Bacon {
  fun eat() {
    print "Crunch crunch crunch!";
  }
}

Bacon().eat(); // Prints "Crunch crunch crunch!".

class Thing {
  fun getCallback() {
    fun localFunction() {
      print this;
    }
    return localFunction;
  }
}

var callback = Thing().getCallback();
callback();

Cleaning Up Compiled Files

After running Zealot, you may want to clean up compiled files. Use the following commands:

For Linux and macOS:

make clean

For Windows:

Get-ChildItem -Path .\com\piscan\zealot -Filter *.class -Recurse | Remove-Item -Force

These commands will remove all compiled .class files, ensuring a clean environment.