https://github.com/ners/dosh

The power of Haskell in your terminal!
https://github.com/ners/dosh

haskell shell

Last synced: 2 months ago
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The power of Haskell in your terminal!

• Host: GitHub
• URL: https://github.com/ners/dosh
• Owner: ners
• License: gpl-3.0
• Created: 2023-01-30T19:09:27.000Z (almost 2 years ago)
• Default Branch: main
• Last Pushed: 2024-07-28T19:37:53.000Z (5 months ago)
• Last Synced: 2024-10-12T00:24:03.876Z (3 months ago)
• Topics: haskell, shell
• Language: Haskell
• Homepage:
• Size: 317 KB
• Stars: 41
• Watchers: 6
• Forks: 3
• Open Issues: 3
• Metadata Files:
  • Readme: README.md

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README

        


# dosh

The power of ~~capitalism~~ Haskell in your terminal!

## What have we got here?

`dosh` is a Haskell Read-Eval-Print Loop, or REPL for short.

While other REPLs for Haskell exist, this one aims to be good enough to replace Bash as a daily driver.

We offer:

- syntax highlighting

- advanced history interaction

- LSP-powered autocompletion and error detection

## Really? *Haskell* as a daily driver?

Why not? Haskell is an advanced functional programming language with an excellent blend of power and elegance that scales well as commands grow nontrivial.

> This is the Unix philosophy: Write programs that do one thing and do it well. Write

> programs to work together. Write programs to handle text streams, because that is a

> universal interface.

— Doug McIlroy

Aside from executing programs, an essential operation of the shell is to manipulate text streams that pass between programs.

Many programs output structured data, which Bash is [notoriously bad at handling](https://stackoverflow.com/a/45201229).

There are many alternatives to Bash, but they are all fundamentally boring shells. They tend to invent new domain specific languages which ultimately offer no real value as a programming language.

Instead of inventing a new shell language that can do slighty more than Bash, why not go the other way around and make an existing language usable as a shell?

And what language is more suitable than one that was quite literally invented as a testbed for novel uses such as this?

## Why is it named `dosh`?

Because our REPL has special handling of Haskell's [`do` notation](https://en.wikibooks.org/wiki/Haskell/do_notation).

In Haskell, the keyword `do` introduces a block of commands that evaluate sequentially and can depend on each other.

When the user enters a `do` block in `dosh`, the prompt changes to `do$`, which is also where the logo comes from.

I've also been advised to avoid overt references to Haskell in the name (e.g. `hashell`, `shellmonad`), as those might spook people.

## Prior art

This is not a novel idea, as evidenced by the abundance of Haskell libaries that provide shell primitives.

The only novelty of this project is a snazzy REPL around them.

- [turtle: Shell programming, Haskell-style](https://hackage.haskell.org/package/turtle)

- [shh: Simple shell scripting from Haskell](https://hackage.haskell.org/package/shh)

- [shelly: shell-like (systems) programming in Haskell](https://hackage.haskell.org/package/shelly)

- [ptGHCi](https://github.com/litxio/ptghci) is a high-powered REPL for Haskell, inspired by IPython

- [Using Haskell as my shell](https://las.rs/blog/haskell-as-shell.html) (2021) by Las Safin

- [Use Haskell for shell scripting](https://www.haskellforall.com/2015/01/use-haskell-for-shell-scripting.html) (2015) by Gabriella Gonzalez