Yi

Yi is a text editor written in Haskell and extensible in Haskell. The goal of Yi is to provide a flexible, powerful and correct editor core scriptable in Haskell.

Its features include

• a purely functional editor core;
• keybindings written as parsers of the input;
• Emacs, Vim and Cua (subset) emulations provided by default;
• Vty (terminal) and Gtk-based Pango UIs

The long term goal of the project is to make Yi the editor of choice for the haskell hacker. The main short term goal is to maximize Yi's Fun Factor. This means that we want to

• improve hackability (and therefore architecture) and
• add cool features.

We also want to simplify the core Yi package to make it more accessible, splitting some parts into several packages.

Other information (much of it old) is available on the Haskell wiki.

Installing

Yi requires the Haskell Platform 2011.2.0.0 at minimum (for GHC 7, alex, and cabal-install, among other things).

With the Haskell Platform installed, yi should be installed with cabal-install:

$ cabal update
$ cabal install yi

On Linux systems, you'll probably need ncurses development headers for the Vty frontend. On Ubuntu, you'll need to install the libncurses5-dev package.

You can specify frontends to compile, also:

$ cabal install yi -fvty -fpango

Options are -fvty and -fpango.

You can also install the yi-contrib package, which contains some extra contributed things (like user configs):

$ cabal install yi-contrib

If you're in the source repository, you can install yi from source:

$ cabal update # Still update to get updated dependencies
$ (cd yi && cabal install)

And the contrib package:

$ (cd yi-contrib && cabal install)

Getting Source

Yi source repository is available on GitHub.

To get the git version,

$ git clone git://github.com/yi-editor/yi.git

(There may be more repositories in the future, as yi is split more.)

Reporting Bugs

Please report issues on GitHub.

Mailing List

Our mailing list is yi-devel, hosted at Google Groups. Please ask us questions on this list! All development discussion occurs on this list.

IRC channel

Our channel is #yi at Freenode. Please note that it is rather slow (very slow compared to #haskell), so be prepared to stay for longer than 5 minutes.

Configuring Yi

Yi uses the Dyre package to have dynamic reconfiguration. You can configure Yi by creating ~/.config/yi/yi.hs, and then Yi is reconfigured whenever you update this file. Example configuration files are in yi/examples/ (copy any of these into ~/.config/yi/ as yi.hs and restart Yi).

You can also use the sample user configs in the yi-contrib package (see the list of user configs in the source repository on GitHub). To use one of these configurations, install the package and then create a configuration file ~/.config/yi/yi.hs like this:

import Yi
import Yi.Config.Users.Anders

main = yi config

It's possible to customize even these user configs in the same way as the example configurations.

Frontend Compatibility

        |  Vty    Pango
--------+----------------
Linux   |   X       X
OSX     |   X       X
Windows |           X

Windows support for Vty may eventually come; patches on the vty package would certainly be appreciated.

The plan is to move the UI frontends into separate packages, but this has not yet happened.

Profiling

If you're interested in optimizing Yi, this thread may be of use.

Reading material

There are some papers which might interest you. If you plan on hacking on Yi, it's very recommended that you read these

• An editor in Haskell for Haskell

• Lazy Functional Incremental Parsing in Yi

• A JavaScript Mode for Yi

• Robust & Precise incremental parsing of Haskell talks about the precise Haskell mode.