kyn/README.md

# Kyn programming language

Kyn is a simple, easily extensible scripting language written in C++. The syntax is inspired by C and shell languages. It is quite fast. Kyn uses the `.kyn` file extension.

## Features

* Speedy: 20-40% faster than Python
* Simple Syntax: A small amount of keywords makes Kyn easier to master
* Small Codebase: 931 lines of code at the time of writing
* Easily Extensible: The modules system allows anyone to write and contribute their own modules
* Flexible Licensing: Kyn is licensed to you under the Mozilla Public Licence v2.0, meaning you can develop your own modules and keep them to yourself, while keeping the core interpreter open.

## Compiling

Install `make` and your favourite C++ compiler. Then, run `make`. Change the `compiler` variable if required. Ensure that your compiler supports C++14.

## Syntax

Kyn is made up of "modules", which you can call on to collect, process, and output data. Use the `println` module to print something to the console:

```
println "Hello from Kyn!"
```

You can use the output from one module inside another by enclosing it with `(`parenthases`)`, similar to how some shells work.

```
println (math 10 * 3 + 2)
```

This will print the result of 10 * 3 + 2 (which happens to be 32.)

You can initialise variables with the `let` module, and access variables by prefixing a `$` dollar sign.

```
let myVar = "hello!"
println $hello
```

Reassigning variables is done like most programming languages.

```
let myVar = "hello!"
myVar = "goodbye!"
```

Control flow can be done through `if` and `while` (which are technically also modules, but they work in a special way.) The `compare` module can be used for comparisons between things. When using `if` and `while`, there's no need to surround your condition in brackets.

```
let varA = 120
let varB = 130

if compare $varA < $varB {
    println "This code will run!"
} else {
    println "This code won't run."
}

let counter = 0

while compare $counter <= 10 {
    counter = ($counter + 1)
    println $counter
}
```

Full details of the syntax is in `docs/syntax.md`.

## Developing Modules

Modules are held in the `src/modules` folder. There are three steps to implementing a module:

1. Write the module code: Add all the logic and processing in a new folder, with a header file and C++ source file.

2. Update `src/defs/defs.cpp`, `src/executor/executor.cpp` and `src/defs/defs.h`: In these files add references to your new module, to integrate it into the Kyn interpreter.

3. Run `make` to build again. `make` should automatically detect your new module and compile it, as well as recompiling `defs.cpp` and `executor.cpp`, before building the executable.

A full tutorial on writing modules will be released later.

## License

Kyn is licensed under the Mozilla Public Licence v2.0.