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Try Kata

A language,
from first
principles.

KataScript is a small, expression-oriented programming language.

Try Kata Read the Book →

Try a closure

Run this example, or step through it to see how each counter keeps its own state.

Walk through the project →
func make_counter(start: Int, step: Int): Func {
    let value = start
    ret func(): Int {
        value = value + step
        ret value
    }
}
let next = make_counter(0, 1)
let tens = make_counter(0, 10)
print("next: {next()}")
print("next: {next()}")
print("tens: {tens()}")
print("next: {next()}")
print("tens: {tens()}")

Learn KataScript

Get your bearings

Install kata, run a file, and find your way around the workbench.

Read the docs

Read the Book

Learn in sequence through language chapters and complete runnable projects.

Open the Book

Look it up

Find syntax, operators, types, and generated API documentation.

Browse reference

Inside the interpreter

Kata is a personal language workbench: a Rust interpreter, a terminal REPL, and a standard library written partly in KataScript itself.

See the language status for supported features and known limits.

Look inside the repository ↗
  1. 01
    SourceYour program, in a .ks file.
    let n = 42
  2. 02
    Tokens & syntaxA lexer and parser give it structure.
    --dump-ast
  3. 03
    ExecutionValues, scopes, and runtime checks.
    42 : Int

From the Blog

All posts →
Design note

A closure keeps a binding

A small counter reveals what a function carries out of the scope where it was created.

Update

A home for KataScript

A new place for the language guide, practical tutorials, and examples you can inspect and run.

Design note

Three ways to name a type

Why KataScript separates product types, sum types, and interfaces into kind, enum, and type.