# ghc-mod: Happy Haskell Hacking [![build status](https://gitlab.com/dxld/ghc-mod/badges/master/build.svg)](https://gitlab.com/dxld/ghc-mod/commits/master) ghc-mod is a couple of different things depending on what you want to do, you should read the corresponding section: - for [all Haskell developers (Using ghc-mod in your development environment)](#using-ghc-mod-in-your-development-environment) - for [people developing Haskell IDEs (Using ghc-mod as an IDE backend program)](#using-ghc-mod-as-an-ide-backend-program) - for [developing Haskell tooling (Using ghc-mod as a library)](#using-ghc-mod-as-a-library) ## Overview ### Using ghc-mod in your Development Environment To use `ghc-mod` in your development environment of choice you need two things: - The `ghc-mod` program included in the package of the same name, see [Installing](https://github.com/DanielG/ghc-mod/wiki/Installing) - A ghc-mod frontend to integrate it into your development environment, see [Frontend](https://github.com/DanielG/ghc-mod/wiki/Frontend) ### Using ghc-mod as an IDE Backend Program Directly using ghc-mod is while still supported for the time being discouraged. You should look into working with [`haskell-ide-engine`](https://github.com/haskell/haskell-ide-engine) instead. The `ghc-mod` backend program is somewhat crusty and carries a lot of legacy baggage so going forward we would like to see frontends use `haskell-ide-engine` instead. There we're trying to get the design right from the beginning and fix the fragmentation of the Haskell Tooling Ecosystem along the way. ### Using ghc-mod as a Library Internally ghc-mod uses the Glasgow Haskell Compilers's API to implement most of it's functionality. In order to provide a hassle free experience to users ghc-mod tries hard to automatically, and correctly, detect and if needed tweak the environment GHC needs. It also handles some of the more cumbersome parts of getting a working compiler session up and running. This functionality can be very useful to all kinds of Haskell development tools therefore want to expose all the useful abstractions ghc-mod provides. Right now the ghc-mod API is pretty messy a result major internal rewrites and reorganization coupled with too little time for cleanups over the course of almost 100 releases! We would like to make a cut during v6.0 or so and completely re-do the API but we need more input from downstream tool writers to do that properly, see [Library API Redesign](Library-API-Redesign.md). Right now tools like Alanz's [The Haskell Refactorer (HaRe)](https://github.com/alanz/HaRe) and [mote](https://github.com/imeckler/mote) use this environment handling so they can concentrate on their core functionality instead of worrying about environments. Most recently the [`haskell-ide-engine`](https://github.com/haskell/haskell-ide-engine) project has sprung up and if you're planning to write any kind of tool that needs editor integration eventually you should definetly look into that. `haskell-ide-engine` does uses `ghc-mod` at it's core so you'll want to be familliar with it either way. API "documentation" is here: [Hackage docs](http://hackage.haskell.org/package/ghc-mod-5.4.0.0/docs/Language-Haskell-GhcMod.html). ## IRC If you have any problems, suggestions, comments swing by [\#ghc-mod (web client)](https://kiwiirc.com/client/irc.freenode.org/ghc-mod) on Freenode. If you're reporting a bug please also create an issue [here](https://github.com/DanielG/ghc-mod/issues) so we have a way to contact you if you don't have time to stay. Do hang around for a while if no one answers and repeat your question if you still haven't gotten any answer after a day or so. You're most likely to get an answer during the day in GMT+1.