Kley (Pre-Alpha!)

An elegant language for system automation and utilities. Kley strives to make writing maintainable shell scripts convenient and easy.

Caution

This language is currently in the proof-of-concept stage, and there will be many breaking changes.

Contents

• Overview
• Examples
• Other

Overview

Kley is a shell scripting language, designed specifically for running commands and manipulating their inputs/outputs. Most commonly used examples of shell scripting languages are simply shells such as Bash or Powershell, but those introduce heavy compromises when writing scripts.

Shell scripts are notorious for becoming unmaintainable and excessively complicated as they grow. By not trying to also be a shell and having shell scripts in mind from the start, Kley scripts is able to be significantly cleaner and have features which fit well in scripts but are antithetical to a shell.

Note

Kley is not designed to be a shell. Kley's philosophy is that good shells make poor programming languages, and good programming languages make poor shells. By embedding a simple shell into the language, it can have the best of both for scripts.

Examples

TODO

Other

Current Project State

Kley currently has the bare minimum implemented to write a few demo scripts, and nothing more. The primary focus right now is planning and filling out the core features to start transitioning the scripts I use to Kley.

For the time being, performance is intentionally being completely ignored in favor of developing a reliable and intuitive language.

Caution

For now, anything may change at any time.

Core Features, TODO for v0.1 release

• Lexer, Parser, Interpreter
• Basic types: int, str, bool, list<T>, unit
• Internal shell / command mode + types: command, output
• Functions
• Basic control flow: if, while

Planned before v1.0 release

• REPL
• Error handling (tightly integrated with command mode)
• Complete type system: float, tuple, map<K, V>, structs, enums
• JSON: builtin json type, with decoding and encoding
• Generics (or similar? no clear plan yet!)
• Module system / standardized way to cleanly split code into multiple files
• Kley scripts invoking other Kley scripts can call them as a function
• Transpiler to Bash (similar goal as amber)
• JIT Compiler (cached compilation for scripts which run often?)

Pronounciation/Meaning

"kley" is a transliteration of the Ukrainian word "клей", meaning "glue". It is pronounced (almost) identically to the English word "clay".

Alternatives

• Hush has similar goals and execution, with the primary differences being a lua-like syntax and a Bash-like internal shell.
• Amber is a type-safe modern language which is transpiled to Bash.
• Oils focuses on improving the experience of writing shell scripts.
• Koi is a minimalistic shell scripting language which merges a simple language with common shell behaviors.
• sh or the lua version luash provide clean shell integration into python or lua.
• Nushell and Elvish both make a very strong case for a shell being able to be a solid programming language.