Complete README for layer

Author: non-Jedi

layers/+lang/julia/README.org

@@ -8,6 +8,8 @@
 - [[#description][Description]]
   - [[#features][Features:]]
 - [[#install][Install]]
+  - [[#lsp][LSP]]
+- [[#options][Options]]
 - [[#key-bindings][Key bindings]]
   - [[#editing][Editing]]
   - [[#repl][Repl]]
@@ -28,6 +30,46 @@ To use this configuration layer, add it to your =~/.spacemacs=. You will need to
 add =julia= to the existing =dotspacemacs-configuration-layers= list in this
 file.
 
+** LSP
+This layer can be used with [[https://github.com/JuliaEditorSupport/LanguageServer.jl][=LanguageServer.jl=]] and emacs [[https://github.com/emacs-lsp/lsp-mode][=lsp-mode=]] to provide
+richer, IDE-like capabilities. To use this layer with lsp, you must do the
+following:
+
+1. Add =lsp= to =dotspacemacs-configuration-layers=.
+2. Install =LanguageServer.jl= by invoking =Pkg.add("LanguageServer") in the
+   Julia REPL.
+3. Enable layer integration with lsp as described in section below.
+
+=LanguageServer.jl= tends to have a very long startup time. In the worst case,
+=lsp-mode= might give up on the language server before its started, but
+regardless usage of =lsp-mode= with Julia can cause long delays when first
+opening files. To mitigate this issue, you can try compiling =LanguageServer.jl=
+ahead of time using [[https://github.com/JuliaLang/PackageCompiler.jl][=PackageCompiler.jl=]] this drastically reduces startup time
+if successful.
+* Options
+While =julia-mode= is perfectly usable without configuration or other packages,
+you can choose to replace the default functionality of using [[https://github.com/tpapp/julia-repl/][=julia-repl=]] as the
+layer's interactive REPL with the ess REPL and other functionality that comes
+with it. To do so, install this layer with:
+
+#+BEGIN_SRC emacs-lisp
+  (setq-default
+   dotspacemacs-configuration-layers
+   '(
+     (julia :variables julia-mode-enable-ess t)))
+#+END_SRC
+
+This layer also includes experimental support for =lsp-mode=. To enable language
+server functionality with this layer, follow [[#lsp][the instructions for installation]],
+and then install this layer with:
+
+#+BEGIN_SRC emacs-lisp
+  (setq-default
+   dotspacemacs-configuration-layers
+   '(
+     (julia :variables julia-mode-enable-lsp t)))
+#+END_SRC
+
 * Key bindings
 
 | Key Binding | Description                                          |