https://github.com/ners/dosh
📺 The power of Haskell in your terminal!
https://github.com/ners/dosh
frp haskell shell terminal
Last synced: 4 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 3 years ago)
- Default Branch: main
- Last Pushed: 2025-05-20T17:37:56.000Z (8 months ago)
- Last Synced: 2025-07-05T04:14:43.749Z (7 months ago)
- Topics: frp, haskell, shell, terminal
- Language: Haskell
- Homepage:
- Size: 325 KB
- Stars: 43
- Watchers: 6
- Forks: 3
- Open Issues: 3
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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