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Rasa (Rah-zah)

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Embarrassingly modular customizable text editor built in Haskell.

Rasa Editor

A Rasa editing session with multiple cursors & viewports.

Documentation

You can find hackage documentation for rasa and some extensions here:

What people are saying

Excessively Modular! - some bald guy

I'm glad I'm unemployed so I have time to configure it! - my mate Steve

You should go outside one of these days. - Mother

Getting started

Configuring Rasa

Rasa is designed to be easy to configure and script, both when adding extensions provided by the community, and when writing your own user-scripts.

Rasa is written in Haskell, and the configuration is done in the Haskell language, don't let that scare you though, you can script Rasa and add extensions without knowing much haskell!

Building Your First Extension

^ That guide will walk you through installation and getting running! Once you're running rasa you can experiment with creating your own adaptations. You should customize your keymap to add a few mappings you like. It's a short step from here to developing your own extensions. Actions like you'd use in an extension can be registered to listeners in your Main.hs. You can build and experiment with entire extensions in your config file and extract them as a package when you're ready, kind of like a vimrc file. Again, just read the extension guide, it covers what you need to know!

If you have any issues (and I'm sure there'll be a few; it's a new project!) please report them here.

Core Principles

Rasa is meant to be about as modular as an editor can be. The goal is for as much code as possible to be extracted into composable extensions. If the core editing facilities can't be implemented as extensions, then the extension interface isn't powerful enough. I've taken this to its extreme, for instance the following features are implemented as rasa extensions that anyone in the community could have written.

This approach has some unique pros and cons:

Pros

Cons

Core Features

As stated above, the editor itself focuses primarily on easy extensibility, so it doesn't have a lot of editing features built in, instead it focuses on standardizing a good extension API. We focus on creating a simple system so people can pick it up quickly.

Here are some features of that API:

Event Listener System

All actions in the editor are triggered via an event/listener system. Extensions may subscribe to events from the editor, or from another extension and perform an action in response. The Event which triggered the listener is available as an argument). Extensions may also dispatch any kind of event at any time which other extensions may listen for.

Actions/BufActions

Extensions define things that they'd like to do using a powerful set of functions which they can embed in an Action. Within an action an extension may perform IO, access the available buffers, store and access extension state, and edit text.

Running Tests

Run all tests:

Run only tests for core editor:

Installation

At the moment you must build Rasa from source;

To provide reproducible builds, Rasa uses Stack & Nix.

  1. Install stack
  2. Install nix
  3. Clone this repo and cd into the directory
  4. Run stack build && stack exec rasa (you may want to alias this to rasa)

Installation without nix (not-recommended)

  1. Install stack
  2. Clone this repo and cd into the directory
  3. Run stack build --no-nix && stack exec rasa --no-nix (you may want to alias this to rasa)

Troubleshooting

If you have issues with nix; you may try running rasa without it with stack build --no-nix && stack exec rasa; You'll likely have to consider the following:

extra-lib-dirs:
- /usr/local/opt/icu4c/lib 
extra-include-dirs:
- /usr/local/opt/icu4c/include
# in stack.yaml
extra-deps:
- rasa-0.1.0.0
- rasa-ext-cursors-0.1.0.0
- rasa-ext-logger-0.1.0.0
- rasa-ext-vim-0.1.0.0
- text-lens-0.1.0.0
- rasa-ext-files-0.1.0.0
- rasa-ext-cmd-0.1.0.0
- rasa-ext-slate-0.1.0.0
- vty-5.14

Contributing

Things are moving quickly, but I'd love a hand! You can get a rough idea of where you can help out at the Roadmap, feel free to leave a comment there asking any questions.

Chatting about features is a key part of Rasa's development; come join us in the Chat Room!