KinderScript

A simple, kid-friendly programming language interpreter written in Kotlin!

Version 1.2.0 - See CHANGELOG.md for version history.

Overview

KinderScript is designed to introduce children to programming concepts in a fun and accessible way. It features a simple syntax with commands for printing messages, performing math operations, defining functions, creating loops, making decisions with conditionals, and storing data in variables.

Features

• Simple Commands: Easy-to-understand syntax
• Math Operations: Add, subtract, multiply, divide, modulo, and power
• Functions: Define and call reusable functions with parameters
• Loops: Repeat blocks of code (including nested loops)
• Variables: Store and use variables with set command
• Conditionals: Make decisions with if/else statements
• Error Handling: Clear error messages for common mistakes
• Versioning: Built-in version tracking and display

Installation

Prerequisites

• Java 8 or higher
• Kotlin compiler (optional, for building from source)

Quick Start

1. Compile the interpreter (if needed):

   kotlinc KinderScript.kt -include-runtime -d KinderScript.jar

2. Check the version:

   java -jar KinderScript.jar --version

3. Run a KinderScript program:

   java -jar KinderScript.jar program.kinder

Complete Examples

Copy any of these examples into a .kinder file and run them instantly!

Example 1: Your First Program

Learn: Basic output with say

say Hello, World!
say Welcome to KinderScript!
say Programming is fun!

Output:

Hello, World!
Welcome to KinderScript!
Programming is fun!

---

Example 2: Math Operations

Learn: Performing calculations with add, subtract, multiply, and divide

say Let's do some math!

say Adding numbers:
add(5, 3, 2)

say Subtracting numbers:
subtract(20, 5, 3)

say Multiplying numbers:
multiply(4, 3, 2)

say Dividing numbers:
divide(100, 5, 2)

Output:

Let's do some math!
Adding numbers:
Result of add: 10
Subtracting numbers:
Result of subtract: 12
Multiplying numbers:
Result of multiply: 24
Dividing numbers:
Result of divide: 10

---

Example 3: Functions with Parameters

Learn: Creating reusable functions that accept parameters

function introduce($name, $hobby) {
say Hi! My name is $name
say I love $hobby
say Nice to meet you!
}

call introduce(Alice, reading)
call introduce(Bob, coding)
call introduce(Charlie, drawing)

Output:

Hi! My name is Alice
I love reading
Nice to meet you!
Hi! My name is Bob
I love coding
Nice to meet you!
Hi! My name is Charlie
I love drawing
Nice to meet you!

---

Example 4: Simple Loops

Learn: Repeating code with repeat

say Counting to 5:
repeat 5 {
say I can count!
}

say Let's sing Happy Birthday:
repeat 4 {
say Happy Birthday!
}

Output:

Counting to 5:
I can count!
I can count!
I can count!
I can count!
I can count!

Let's sing Happy Birthday:
Happy Birthday!
Happy Birthday!
Happy Birthday!
Happy Birthday!

---

Example 5: Nested Loops

Learn: Loops inside loops for complex patterns

say Creating a pattern:
repeat 3 {
say Row number
repeat 2 {
say  Item
}
}

Output:

Creating a pattern:
Row number
 Item
 Item
Row number
 Item
 Item
Row number
 Item
 Item

---

Example 6: Functions with Loops

Learn: Combining functions and loops

function celebrate($name) {
say Happy celebration, $name!
repeat 3 {
say Cheers!
}
say Party time!
}

function sing($name) {
say Let's sing for $name!
repeat 2 {
say Happy birthday to $name!
}
}

call celebrate(Emma)
call sing(Lucas)

Output:

Happy celebration, Emma!
Cheers!
Cheers!
Cheers!
Party time!

Let's sing for Lucas!
Happy birthday to Lucas!
Happy birthday to Lucas!

---

Example 7: Complete Program - Birthday Card Generator

Learn: Putting it all together

function birthdayCard($name, $age) {
say ============================
say Happy Birthday, $name!
say ============================
say You are turning $age years old!
say Let's celebrate:
repeat 3 {
say Hip hip hooray!
}
say Have an amazing day!
say ============================
}

call birthdayCard(Sarah, 8)
call birthdayCard(Max, 10)

Output:

============================
Happy Birthday, Sarah!
============================
You are turning 8 years old!
Let's celebrate:
Hip hip hooray!
Hip hip hooray!
Hip hip hooray!
Have an amazing day!
============================
============================
Happy Birthday, Max!
============================
You are turning 10 years old!
Let's celebrate:
Hip hip hooray!
Hip hip hooray!
Hip hip hooray!
Have an amazing day!
============================

---

Example 8: Math Calculator

Learn: Using math operations in a practical way

say Math Calculator Demo

say Adding my test scores:
add(85, 90, 92, 88)

say Finding the total cost:
multiply(5, 3)

say Calculating change:
subtract(100, 35, 12)

say Sharing equally:
divide(24, 3)

Output:

Math Calculator Demo

Adding my test scores:
Result of add: 355
Finding the total cost:
Result of multiply: 15
Calculating change:
Result of subtract: 53
Sharing equally:
Result of divide: 8

---

Quick Reference

All Available Commands

Command	Description	Example
say	Print a message	say Hello!
set	Assign a variable	set $age = 10
if	Conditional statement	if $age >= 18 { say Adult }
else	Alternative block	if $x > 0 { say Positive } else { say Negative }
add()	Add numbers	add(5, 3, 2)
subtract()	Subtract numbers	subtract(10, 3)
multiply()	Multiply numbers	multiply(4, 2)
divide()	Divide numbers	divide(100, 5)
modulo()	Remainder after division	modulo(17, 5)
power()	Exponentiation	power(2, 8)
function	Define a function	function greet($name) { say Hello $name }
call	Call a function	call greet(Alice)
repeat	Repeat code	repeat 5 { say Hi }

Important Notes

• Variables in strings: Use $variableName to insert variables into text
• Variable assignment: Use set $name = value to store values (numbers or strings)
• Conditions: Support ==, !=, <, >, <=, >= operators
• Function parameters: Use $paramName in function definitions
• Math operations: Must use literal numbers (e.g., add(5, 3), not add($x, $y))
• Division by zero: Not allowed - will show an error
• Function calls: Must match parameter count exactly
• Version: Check version with java -jar KinderScript.jar --version

More Examples

See program.kinder for additional advanced examples demonstrating all language features.

Error Handling

KinderScript provides clear error messages for:

• Division by zero
• Empty math operations
• Function parameter/argument mismatches
• Missing functions
• Invalid syntax

Project Structure

KinderScript/
├── KinderScript.kt    # Main interpreter source code
├── KinderScript.jar   # Compiled executable
├── program.kinder     # Example program
├── README.md          # This file
└── LICENSE            # MIT License

Development

Building from Source

kotlinc KinderScript.kt -include-runtime -d KinderScript.jar

Running Tests

Test the interpreter with the example program:

java -jar KinderScript.jar program.kinder

Language Limitations

• Variables can only be used in string interpolation and conditions (not in math operations)
• Math operations require literal numbers
• Functions must be defined before they are called

Future Improvements

• Add Gradle support
• Add to Homebrew
• Add support for variables in math operations
• Add arrays/lists support
• Add string manipulation functions
• Add file I/O operations

Changelog

See CHANGELOG.md for a detailed list of changes and version history.

License

MIT License - See LICENSE file for details

Author

Anu S Pillai