#interpreters #wasm #programming-language #cli

bin+lib skiff

An immutability-first, functional scripting language with a friendly syntax and compiler/interpreter written in Rust!

5 releases

0.4.5 Sep 6, 2021
0.4.4 Sep 6, 2021
0.4.3 Aug 13, 2021
0.4.0 Jul 18, 2021
0.3.0 Jun 14, 2021

#8 in Programming languages

Download history 1/week @ 2022-01-27 5/week @ 2022-02-17 1/week @ 2022-02-24 2/week @ 2022-03-03 5/week @ 2022-03-10 31/week @ 2022-03-17 2/week @ 2022-04-07 41/week @ 2022-04-28 35/week @ 2022-05-05 83/week @ 2022-05-12

159 downloads per month

MIT license

145KB
4K SLoC

Skiff

A gradually-typed, functional scripting language with a friendly syntax and interpreter written in Rust!

Running

You can run Skiff in the Skiff web editor (powered by WASM!).

If you prefer to use your own text editor, you can install Skiff from crates.io and run it from the command line

cargo install skiff
skiff <filename> # make sure installed crate binaries are in your PATH

About

Skiff started as a personal project for me to learn more about the design and implementation of programming languages. It was a mash-up of ideas and syntaxes from existing languages. As it evolved, however, it became a platform for me to learn about different algorithms like HM type inference and exhaustiveness checking of pattern match expressions.

Next on the road map is an exploration of gradual typing by adding a typed keyword to distinguish fully type functions from partially typed functions. By default, Skiff will have very few static guarantees. However, you can opt into more checks within a given function by fully annotating the arguments and return type or using the typed keyword to tell Skiff to infer a function type. The goal is to have a language that is as easy to use as a dynamically-typed language while offering some of the guarantees and in-code documentation of statically-typed languages.

What does it look like?

# function definition (types are optional)
def fact(n: Number) -> Number:
    match n:
        | 1 => 1
        | n =>
            let next = fact(n - 1)
            next * n
    end
end
# conditionals
let cond: Boolean = true
if cond:
    1
elif false:
    2
else:
    3
end
# algebraic datatypes (types are optional)
data Option:
    | some(v: Number)
    | empty()
end
# pattern matching
match some(1):
    | some(n) => n
    | empty() => 0
end
# anonymous functions
let increment: Number -> Number = lambda(n): n + 1 end
let add: (Number, Number) -> Number = lambda(a,b): a + b end

Language Reference

Full docs are a work in progress. To get an idea of what the features and syntax look like, you can look at the language tour test file.

Developing

Clone the repo to work on Skiff. You can run a local development version using

cargo run -- <filename>

For example:

cargo run -- tests/files/success/plus_and_times_precedence.boat

Features

Language Features:

Tree Walk Interpreter Bytecode Interpreter
Arithmetic
Equality Operators
Conditionals
Functions
Recursion
Lambdas
Let binding
Improved Error Reporting
Type Annotations
Type Inference
Algebraic Datatypes
Pattern Matching
Exhaustiveness Checking
Call Stack Traces
Parameterized Types
typed keyword
Strings
File Operations
Testing Constructs

Miscellaneous:

  • REPL
  • Language Reference
  • Web Editor (WASM)
  • Continuous Integration
  • Publish crate

Dependencies

~4.5MB
~78K SLoC