lsp-erlang: Add initial support for erlang-language-platform (#4122)

Supports erlang-ls and erlang-language-platform.
emacs-lsp · Aug 6, 2023 · 5c36d25 · 5c36d25
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diff --git a/CHANGELOG.org b/CHANGELOG.org
@@ -1,5 +1,6 @@
 * Changelog
 ** Unreleased 8.0.1
+  * Add [[https://github.com/WhatsApp/erlang-language-platform][erlang-language-platform]] support in lsp-erlang client.
   * Add [[https://github.com/elixir-tools/credo-language-server][credo-language-server]]
   * Add support for clojure-ts-mode in clojure-lsp client
   * terraform-ls now supports prefill required fields and the ability to validate on save.

diff --git a/clients/lsp-erlang.el b/clients/lsp-erlang.el
@@ -1,8 +1,8 @@
 ;;; lsp-erlang.el --- Erlang Client settings         -*- lexical-binding: t; -*-
 
-;; Copyright (C) 2019 Roberto Aloi
+;; Copyright (C) 2019-2023 Roberto Aloi, Alan Zimmerman
 
-;; Author: Roberto Aloi
+;; Author: Roberto Aloi, Alan Zimmerman
 ;; Keywords: erlang lsp
 
 ;; This program is free software; you can redistribute it and/or modify
@@ -27,40 +27,128 @@
 (require 'lsp-mode)
 
 (defgroup lsp-erlang nil
-  "LSP support for the Erlang programming language, using erlang-ls"
+  "LSP support for the Erlang programming language.
+It can use erlang-ls or erlang-language-platform (ELP)."
+  :group 'lsp-mode)
+
+(defgroup lsp-erlang-ls nil
+  "LSP support for the Erlang programming language using erlang-ls."
   :group 'lsp-mode
   :link '(url-link "https://github.com/erlang-ls/erlang_ls"))
 
-(defcustom lsp-erlang-server-path
+(defgroup lsp-erlang-elp nil
+  "LSP support for the Erlang programming language using erlang-language-platform (ELP)."
+  :group 'lsp-mode
+  :link '(url-link "https://github.com/WhatsApp/erlang-language-platform"))
+
+(defcustom lsp-erlang-server 'erlang-ls
+  "Choose LSP server."
+  :type '(choice (const :tag "erlang-ls" erlang-ls)
+                 (const :tag "erlang-language-platform" erlang-language-platform))
+  :group 'lsp-erlang
+  :package-version '(lsp-mode . "6.2"))
+
+;; erlang-ls
+
+(defcustom lsp-erlang-ls-server-path
   "erlang_ls"
   "Path to the Erlang Language Server binary."
-  :group 'lsp-erlang
+  :group 'lsp-erlang-ls
   :risky t
   :type 'file)
 
-(defcustom lsp-erlang-server-connection-type
+(defcustom lsp-erlang-ls-server-connection-type
   'stdio
-  "Type of connection to use with the Erlang Language Server: tcp or stdio"
-  :group 'lsp-erlang
+  "Type of connection to use with the Erlang Language Server: tcp or stdio."
+  :group 'lsp-erlang-ls
   :risky t
   :type 'symbol)
 
-(defun lsp-erlang-server-start-fun (port)
-  `(,lsp-erlang-server-path
+(defun lsp-erlang-ls-server-start-fun (port)
+  "Command to start erlang_ls in TCP mode on the given PORT."
+  `(,lsp-erlang-ls-server-path
     "--transport" "tcp"
     "--port" ,(number-to-string port)))
 
-(defun lsp-erlang-server-connection ()
-  (if (eq lsp-erlang-server-connection-type 'tcp)
-      (lsp-tcp-connection 'lsp-erlang-server-start-fun)
-    (lsp-stdio-connection `(,lsp-erlang-server-path "--transport" "stdio"))))
+(defun lsp-erlang-ls-server-connection ()
+  "Command to start erlang_ls in stdio mode."
+  (if (eq lsp-erlang-ls-server-connection-type 'tcp)
+      (lsp-tcp-connection 'lsp-erlang-ls-server-start-fun)
+    (lsp-stdio-connection `(,lsp-erlang-ls-server-path "--transport" "stdio"))))
 
 (lsp-register-client
- (make-lsp-client :new-connection (lsp-erlang-server-connection)
+ (make-lsp-client :new-connection (lsp-erlang-ls-server-connection)
                   :major-modes '(erlang-mode)
                   :priority -1
                   :server-id 'erlang-ls))
 
+
+;; erlang-language-platform
+
+(defcustom lsp-erlang-elp-server-command '("elp" "server")
+  "Command to start erlang-language-platform."
+  :type '(repeat string)
+  :group 'lsp-erlang-elp
+  :package-version '(lsp-mode . "8.0.0"))
+
+(defcustom lsp-erlang-elp-download-url
+  (format "https://github.com/WhatsApp/erlang-language-platform/releases/latest/download/%s"
+          (pcase system-type
+            ('gnu/linux "elp-linux.tar.gz")
+            ('darwin "elp-macos.tar.gz")))
+  "Automatic download url for erlang-language-platform."
+  :type 'string
+  :group 'lsp-erlang-elp
+  :package-version '(lsp-mode . "8.0.0"))
+
+(defcustom lsp-erlang-elp-store-path (f-join lsp-server-install-dir
+                                                "erlang"
+                                                (if (eq system-type 'windows-nt)
+                                                    "elp.exe"
+                                                  "elp"))
+  "The path to the file in which `elp' will be stored."
+  :type 'file
+  :group 'lsp-erlang-elp
+  :package-version '(lsp-mode . "8.0.0"))
+
+(lsp-dependency
+ 'erlang-language-platform
+ `(:download :url lsp-erlang-elp-download-url
+             :decompress :targz
+             :store-path lsp-erlang-elp-store-path
+             :set-executable? t)
+ '(:system "elp"))
+
+;; Client
+
+(lsp-register-client
+ (make-lsp-client
+  :new-connection (lsp-stdio-connection
+                   (lambda ()
+                     `(,(or (executable-find
+                             (cl-first lsp-erlang-elp-server-command))
+                            (lsp-package-path 'erlang-language-platform)
+                            "elp")
+                       ,@(cl-rest lsp-erlang-elp-server-command))))
+  :activation-fn (lsp-activate-on "erlang")
+  :priority (if (eq lsp-erlang-server 'erlang-language-platform) 1 -1)
+  :server-id 'elp
+  :custom-capabilities `((experimental . ((snippetTextEdit . ,(and lsp-enable-snippet (featurep 'yasnippet))))))
+  :download-server-fn (lambda (_client callback error-callback _update?)
+                        (lsp-package-ensure 'erlang-language-platform callback error-callback))))
+
+(defun lsp-erlang-switch-server (&optional lsp-server)
+  "Switch priorities of lsp servers, unless LSP-SERVER is already active."
+  (interactive)
+  (let ((current-server (if (> (lsp--client-priority (gethash 'erlang-ls lsp-clients)) 0)
+                            'erlang-ls
+                          'erlang-language-platform)))
+    (unless (eq lsp-server current-server)
+      (dolist (server '(erlang-ls erlang-language-platform))
+        (when (natnump (setf (lsp--client-priority (gethash server lsp-clients))
+                             (* (lsp--client-priority (gethash server lsp-clients)) -1)))
+          (message (format "Switched to server %s." server)))))))
+
 (lsp-consistency-check lsp-erlang)
 
 (provide 'lsp-erlang)

diff --git a/docs/lsp-clients.json b/docs/lsp-clients.json
@@ -220,13 +220,21 @@
     "debugger": "Not available"
   },
   {
-    "name": "erlang",
+    "name": "erlang-ls",
     "full-name": "Erlang",
     "server-name": "erlang_ls",
     "server-url": "https://github.com/erlang-ls/erlang_ls",
     "installation-url": "https://github.com/erlang-ls/erlang_ls",
     "debugger": "Not available"
   },
+  {
+    "name": "erlang-elp",
+    "full-name": "Erlang",
+    "server-name": "elp",
+    "server-url": "https://github.com/WhatsApp/erlang-language-platform",
+    "installation-url": "https://github.com/WhatsApp/erlang-language-platform",
+    "debugger": "Not available"
+  },
   {
     "name": "eslint",
     "full-name": "ESlint",