Give the readme a significant pass (#1869)

README.md

@@ -3,32 +3,43 @@
 Our vision is that you should build an IDE by combining:
 
 * [`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;
-* `hie-core` (i.e. this library) for defining how to type check, when to type check, and producing messages;
-* [`haskell-lsp`](https://github.com/alanz/haskell-lsp) for sending those messages to an LSP ([Language Server Protocol](https://microsoft.github.io/language-server-protocol/)) server;
-* A [VS Code extension](https://code.visualstudio.com/api), e.g. `extension` in this directory (although the above components enable Haskell IDE features in other editors too).
+* `hie-core` (i.e. this library) for defining how to type check, when to type check, and producing diagnostic messages;
+* 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) for your specific choices of plugin;
+* [`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).
 
 There are more details about our approach [in this blog post](https://4ta.uk/p/shaking-up-the-ide).
 
 ## How to use it
 
-### VS Code
-
-#### Installing the binary
+First install the `hie-core` binary using `stack` or `cabal`, e.g.
 
 1. `git clone https://github.com/digital-asset/daml.git`
 2. `cd daml/compiler/hie-core`
-3. `stack build`
+3. `cabal install` or `stack install` (and make sure `~/.local/bin` is on your `$PATH`)
 
-#### Installing the VSCode extension
+It's important that `hie-core` is compiled with the same compiler you use to build your projects.
+
+Next, check that `hie-bios` is able to load your project. This step is currently a bit difficult.
+
+Next, set up an extension for your editor.
+
+### Using with VS Code
+
+Install the VS code extension
 
 1. `cd compiler/hie-core/extension`
 2. `npm ci`
-3. `vsce package`
-4. `code --install-extension hie-core-0.0.1.vsix`
+3. `npm install vsce --global` (may require `sudo`)
+4. `vsce package`
+5. `code --install-extension hie-core-0.0.1.vsix`
+
+Now openning a `.hs` file should work with `hie-core`.
 
 ### Emacs
 
 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.
+
 ```elisp
 ;;Melpa packages support
 (require 'package)
@@ -51,14 +62,17 @@ There are two things you can do about this warning:
 (package-initialize)
 ;; Remember : to avoid package-not-found errors, refresh the package
 ;; database now and then with M-x package-refresh-contents.
-   ```
+```
+   
 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:
-  - `lsp-haskell`
-  - `lsp-ui`
-  - `flycheck`
-  - `yasnippet`
 
-When done with this, add the following lines to your `.emacs` :
+* `lsp-haskell`
+* `lsp-ui`
+* `flycheck`
+* `yasnippet`
+
+When done with this, add the following lines to your `.emacs`:
+
 ```elisp
 ;; LSP support for Haskell
 (require 'lsp)
@@ -70,6 +84,7 @@ When done with this, add the following lines to your `.emacs` :
 ```
 
 Optionally, you may wish to add the following conveniences:
+
 ```elisp
 ;; Enable LSP logging (helpful for debugging)
 (setq lsp-log-io t)
@@ -79,10 +94,12 @@ Optionally, you may wish to add the following conveniences:
 (define-key flymake-mode-map (kbd "M-p") 'flymake-goto-prev-error)
 ```
 
-Next stop is to build `hie-core`. In the `daml` repository, navigate to `//compiler/hie-core` and invoked `stack build`. This will install the `hie-core` executable into a location along the lines of `$HOME/path/to/daml/compiler/hie-core/.stack-work/install/x86_64-osx/nightly-2019-05-20/8.6.5/bin/hie-core`. You want to get this executable in your `$PATH`. I achieved this with a command like `ln -s ~/path/to/compiler/hie-core/.stack-work/install/x86_64-osx/nightly-2019-05-20/8.6.5/bin/hie-core ~/.local/bin/hie-core` (because `~/.local/bin` is put into my `PATH` in my `~/.bashrc`).
+### Testing
+
+For testing, I've been using the `ghc-lib-gen` target of the [`ghc-lib` project](https://github.com/digital-asset/ghc-lib). Navigate to the root of `ghc-lib` and create an `hie.yaml` file with contents
 
-Time to test things out. It's important to note that for this to work, your programs need to be compiled with the same compiler used to build `hie-core`. For testing, I've been using the `ghc-lib-gen` target of the [`ghc-lib` project](https://github.com/digital-asset/ghc-lib). Navigate to the root of `ghc-lib` and create an `hie.yaml` file with contents
 ```yaml
 cradle: {cabal: {component: "exe:ghc-lib-gen"}}
 ```
-Invoke `cabal new-configure -w ~/.stack/programs/~/.stack/programs/x86_64-osx/ghc-8.6.5/bin/ghc` (this is the `ghc` used by `stack` to build `hie-core` - consult `//compiler/hie-core/stack.yaml` to help work out what you should write here). This last step will create a file `cabal.project.local` with contents pointing `cabal` to use the desired `ghc`. You can build `ghc-lib-gen` from the `ghc-lib` directory with the command `cabal new-build` as you like. After creating `cabal.project.local`, you should be all set. Open `ghc-lib/ghc-lib-gen/src/Main.hs` in an Emacs buffer and, for example, hover should bring up type/definition info.
+
+Invoke `cabal new-configure -w ~/.stack/programs/~/.stack/programs/x86_64-osx/ghc-8.6.5/bin/ghc` (this is the `ghc` used by `stack` to build `hie-core` - consult `//compiler/hie-core/stack.yaml` to help work out what you should write here). This last step will create a file `cabal.project.local` with contents pointing `cabal` to use the desired `ghc`. You can build `ghc-lib-gen` from the `ghc-lib` directory with the command `cabal new-build` as you like. After creating `cabal.project.local`, you should be all set. Open `ghc-lib/ghc-lib-gen/src/Main.hs` in a buffer and, for example, hover should bring up type/definition info.