Quickstart

Install

Koskari publishes to PyPI with wheels for Linux and macOS:

pip install "koskari[repl]"

The repl extra adds syntax highlighting to the REPL. Every release so far is a weekly development snapshot, a pre-release, so pip install koskari resolves to the newest one; once a final release exists, --pre keeps selecting snapshots. To build from a source checkout instead, see Build and test.

First session

Start the REPL:

koskari

The prompt is >>> . Type a form at it and Koskari prints the form’s value on the next line:

>>> (+ 1 2)
3
>>> (print "Hello, Koskari!")
Hello, Koskari!

A form left open at the end of a line continues on the next, under a ... prompt:

>>> (+ 1
...    2)
3

Leave with (exit) or Ctrl-D.

A file

Save this as hello.ki:

(print "Hello, Koskari!")

Run it:

koskari hello.ki

A small program

A .ki file is written in layout: a line with more than one element is a call, and a line ending in : opens an indented block. Parentheses still group nested expressions. Save this as fruits.ki and run it the same way:

var fruits #["apple" "pear" "plum"]

def shout [word]:
    (+ (word.upper) "!")

for-each [fruit fruits]:
    print (shout fruit)

print (len fruits) "fruits, starting with" fruits[0]

APPLE!
PEAR!
PLUM!
3 fruits, starting with apple

(word.upper) calls a Python string method and fruits[0] indexes a Python list. Everything Koskari touches is a Python object.

Compile to bytecode

koskari --compile-kio out.kio hello.ki
koskari --execute-kio out.kio

--compile-kio runs the program as well as writing the .kio, so the first command prints Hello, Koskari! too.

See CLI and configuration for every flag.

Editor setup

Syntax highlighting, and optionally LSP support, for three editors. The files are under editors/ in the repository.

Editor

Included

Setup

Emacs

Major mode: highlighting, indentation, comments

Load editors/emacs/koskari-mode.el; see editors/emacs/README.md

Helix

Tree-sitter grammar and LSP integration

Build the grammar; see editors/helix/README.md

VSCode / TextMate

TextMate grammar for highlighting

Install from the folder or VSIX; see editors/textmate/README.md

For Helix and the language server, install the lsp extra as well:

pip install "koskari[repl,lsp]"

Next