Add readme

crates/lang_srv/README.md

@@ -0,0 +1,66 @@
+# roc_ls
+
+This is a rudimentary language server for supporting basic editor usage in Roc.
+
+Support for the following LSP features are provided:
+
+- Inline diagnostics
+- Hover support to get types of values
+- Go-to-definition
+  !(go-to-definition in roc pg)[./img/go-to-definition.mov]
+  - Note that go-to-definition for the builtins does not yet work.
+  - Go-to-definition for abilities resolves to their specialization, if one exists.
+    !(go-to-definition in roc pg)[./img/go-to-definition-abilities.mov]
+- Formatting Roc files on save
+  !(format)[./img/format.mov]
+
+Semantic highlighting will also be added soon. Additional features require
+changes to the compiler infrastructure that are not yet available.
+
+Note that the language server is a bit naive:
+- If you make a change in a dependency, you'll need to also make a change in
+    the dependents' files for the changes to be picked up
+- The language server will only operate on changes that are also reflected on
+    disk (so save often)
+
+## Installing
+
+At this time, only from-source installations of the binary are supported.
+
+Follow the (installation from source)[https://github.com/roc-lang/roc/tree/main/getting_started#installation] instructions. Then run
+
+```
+cargo build -p roc_lang_srv --release
+```
+
+which will give you a language server binary at
+
+```
+target/release/roc_ls
+```
+
+### Configuring in your editor
+
+Please follow your editor's language server implementation's documentation to see how custom language servers should be configured.
+
+#### [coc.nvim](https://github.com/neoclide/coc.nvim)
+
+Add the following to your coc JSON configuration file:
+
+```
+{
+  "languageserver": {
+    "roc": {
+      "command": "<path to binary folder>/roc_ls",
+      "filetypes": ["roc"]
+    }
+  }
+}
+```
+
+If you're using coc.nvim and want to use the configuration above, be sure to also instruct your vim that `*.roc` files have roc filetype.
+
+## Debug
+
+If you want to debug the server, use [debug_server.sh](./debug_server.sh)
+instead of the direct binary.

crates/lang_srv/debug_server.sh

@@ -1,4 +1,4 @@
 #!/bin/bash
 
 SCRIPT_DIR=$(cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd)
-${SCRIPT_DIR}/../../target/debug/roc_ls "$@" 2> /tmp/rocls.err
+${SCRIPT_DIR}/../../target/debug/roc_ls "$@" 2> /tmp/roc_ls.err