nvim-hs

Neovim API for Haskell plugins as well as a plugin provider. This library and executable should provide a basis for developing plugins. This package should only contain broadly useful interfaces to write plugins for Neovim in haskell. The design goal is to create an easy to use API that avoids most of the boilerplate while still retaining some sense of reliability and type safety. Since Template Haskell is used to generate the neovim bindings and to avoid some of the boilerplate handy work, some exotic operating systems and architectures may not work.

What do I have to expect if I were to use it now?

Check the issue list here on github.

For Windows users

Named pipes are not supported at the momend #103. You therefore have to start nvim-hs instances by connecting to STDIN and STDOUT or TCP. By default nvim-hs connects to the listen socket pointed to by the NVIM environment variable and the functions in the module Neovim.Debug rely on that. If you want to be able to run these functions, start Neovim with nvim --listen localhost: or similar (This example command starts neovim with a socket listening on localhost and random a random TCP port.)

How do I start using this?

You need to install nvim-hs.vim, a plugin that manages starting of nvim-hs plugins. To do that, just follow the instructions outlined here.

Once you have installed nvim-hs.vim, you can use nvim-hs plugins as you would normal vim plugins. Note that every plugin you install is started as a separate process, which should be fine unless you have a lot of them.

Scripting with Haskell

The entry point for all Haskell-based scripts is a plugin. An nvim-hs plugin is a plain Haskell project with two conventions:

1. You need an executable that starts a msgpack-rpc compatible client.

2. You need a tiny bit of vimL in your runtime path that starts the plugin.

The simplest way to get started is using the stack template from this repository/package inside your Neovim configuration folder, but you can also manually create a project by doing everything that is explained in :help nvim-hs.txt (which should be available if you installed nvim-hs.vim as mentioned in the previous section).

To use that template, you'll first need to install stack and have the Neovim executable on the path (the API code generation calls nvim --api-info so it needs access to nvim).

After you've done that, you can run these commands to setup the template (assuming your Neovim configuration folder is in $XDG_CONFIG_HOME/nvim):

$ cd $XDG_CONFIG_HOME/nvim
$ stack new my-nvim-hs \
https://raw.githubusercontent.com/neovimhaskell/nvim-hs/master/stack-template.hsfiles \
--bare --omit-packages --ignore-subdirs

If you start Neovim now, it will compile the example plugins which may take a few minutes. Once it is started you can use the predefined functions from the template, for example by running :echo NextRandom(), which should print a random number.

To start writing your own functions and plugins, read through the files generated by the template and also check out the library documentation on hackage.

Contributing

Documentation, typo fixes, and the like will almost always be merged.

If you want to bring forward new features or convenience libraries for interacting with Neovim, you should create an issue first. The features of this (cabal) project should be kept small as this helps reduce the development time. (For some tests it is necessary to issue cabal install, so any change to to a module can significantly increase the compilation time.) If your idea solves a general problem, feel free to open an issue in the library project of nvim-hs, nvim-hs-contrib.