* [`hie-bios`](https://github.com/mpickering/hie-bios) for determining where your files are, what are their dependencies, what extensions are enabled and so on;
* A bunch of plugins that haven't yet been written, e.g. [`hie-hlint`](https://github.com/ndmitchell/hlint) and [`hie-ormolu`](https://github.com/tweag/ormolu), to choose which features you want;
* [`haskell-lsp`](https://github.com/alanz/haskell-lsp) for sending those messages to a [Language Server Protocol (LSP)](https://microsoft.github.io/language-server-protocol/) server;
* An extension for your editor. We provide a [VS Code extension](https://code.visualstudio.com/api) as `extension` in this directory, although the components work in other LSP editors too (see below for instructions using Emacs).
Next, check that `hie-core` is capable of loading your code. Change to the project directory and run `hie-core`, which will try and load everything using the same code as the IDE, but in a way that's much easier to understand. For example, taking the example of [`shake`](https://github.com/ndmitchell/shake), running `hie-core` gives some error messages and warnings before reporting at the end:
```
Files that worked: 152
Files that failed: 6
* .\model\Main.hs
* .\model\Model.hs
* .\model\Test.hs
* .\model\Util.hs
* .\output\docs\Main.hs
* .\output\docs\Part_Architecture_md.hs
Done
```
Of the 158 files in Shake, as of this moment, 152 can be loaded by the IDE, but 6 can't (error messages for the reasons they can't be loaded are given earlier). The failing files are all prototype work or test output, meaning I can confidently use Shake.
The `hie-core` executable mostly relies on [`hie-bios`](https://github.com/mpickering/hie-bios) to do the difficult work of setting up your GHC environment. If it doesn't work, see [the `hie-bios` manual](https://github.com/mpickering/hie-bios#readme) to get it working. My default fallback is to figure it out by hand and create a `direct` style [`hie.yaml`](https://github.com/ndmitchell/shake/blob/master/hie.yaml) listing the command line arguments to load the project.
The frst step is to install required Emacs packages. If you don't already have [Melpa](https://melpa.org/#/) package installation configured in your `.emacs`, put this stanza at the top.
When this is in your `.emacs` and evaluated, `M-x package-refresh-contents` to get the package database downloaded and then `M-x package-list-packages` to display the available packages. Click on a package to install it. You'll need to install the following packages:
