Introduce YANG LSP support

This addresses #4355

Signed-off-by: Siddharth Sharma <[email protected]>

clients/lsp-yang.el

@@ -0,0 +1,113 @@
+;;; lsp-yang.el --- YANG Client settings         -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2024 Siddharth Sharma
+
+;; Author: Siddharth Sharma <[email protected]>
+;; Keywords: languages, yang, lsp
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; LSP support for YANG using using an external language server. Currently
+;; the supported server is:
+;;
+;; yang-lsp (yls).
+;; See https://github.com/TypeFox/yang-lsp/blob/master/docs/Settings.md
+;; for setting up the project file.
+
+;;; Code:
+
+(require 'lsp-mode)
+
+(defgroup lsp-yang nil
+  "LSP support for the YANG data modeling language using yang-lsp server."
+  :group 'lsp-yang
+  :link '(url-link "https://github.com/TypeFox/yang-lsp"))
+
+(defcustom lsp-yang-yls-executable "yang-language-server"
+  "The yang-lsp server executable to use.
+
+Leave as just the executable name to use the default behavior of finding the
+executable with variable `exec-path'."
+  :group 'lsp-yang
+  :type 'string)
+
+(defcustom lsp-yang-yls-version "0.7.5"
+  "yang-lsp server version to download.
+It has to be set before `lsp-yang.el' is loaded and it has to
+be available here: https://github.com/TypeFox/yang-lsp/releases/"
+  :type 'string
+  :group 'lsp-yang
+  :package-version '(lsp-mode . "8.0.0"))
+
+(defcustom lsp-yang-yls-download-url
+  (format "https://github.com/TypeFox/yang-lsp/releases/download/v%s/yang-language-server_%s.zip"
+          lsp-yang-yls-version
+          lsp-yang-yls-version)
+  "Automatic download url for yang-lsp server"
+  :type 'string
+  :group 'lsp-yang
+  :package-version '(lsp-mode . "8.0.0"))
+
+(defcustom lsp-yang-yls-store-path
+  (f-join lsp-server-install-dir "yang-lsp" "yang-lsp")
+  "The path to the file in which `yang-language-server' will be stored."
+  :type 'file
+  :group 'lsp-yang
+  :package-version '(lsp-mode . "8.0.0"))
+
+(defcustom lsp-yang-yls-binary-path
+  (f-join lsp-server-install-dir (format "yang-lsp/yang-language-server-%s/bin"
+                                         lsp-yang-yls-version)
+          (pcase system-type
+            ('windows-nt "yang-language-server.bat")
+            (_ "yang-language-server")))
+  "The path to `yang-language-server' binary."
+  :type 'file
+  :group 'lsp-yang
+  :package-version '(lsp-mode . "8.0.0"))
+
+(defun lsp-yang--stored-yls-executable ()
+  "Return the stored yang-lsp server executable."
+  (executable-find lsp-yang-yls-binary-path))
+
+(lsp-dependency
+  'yls
+  '(:system "yls")
+  `(:download :url lsp-yang-yls-download-url
+              :decompress :zip
+              :store-path lsp-yang-yls-store-path
+              :binary-path lsp-yang-yls-binary-path
+              :set-exectutable? t))
+
+(lsp-register-client
+ (make-lsp-client
+  :new-connection (lsp-stdio-connection
+                   (lambda () (or (executable-find lsp-yang-yls-executable)
+                                  (lsp-yang--stored-yls-executable)))
+                   (lambda () (or (executable-find lsp-yang-yls-executable)
+                                  (file-executable-p (lsp-yang--stored-yls-executable)))))
+  :activation-fn (lsp-activate-on "yang")
+  :major-modes '(yang-mode)
+  :language-id "YANG"
+  :priority -1
+  :server-id 'lsp-yang
+  :download-server-fn (lambda (_client callback error-callback _update?)
+                        (lsp-package-ensure 'yls callback error-callback))))
+
+(lsp-consistency-check lsp-yang)
+
+(provide 'lsp-yang)
+;;; lsp-yang.el ends here

docs/lsp-clients.json

@@ -1194,6 +1194,14 @@
     "lsp-install-server": "yamlls",
     "debugger": "Not available"
   },
+  {
+    "name": "yang",
+    "full-name": "YANG",
+    "server-name": "yang-lsp",
+    "server-url": "https://github.com/TypeFox/yang-lsp",
+    "installation-url": "https://github.com/TypeFox/yang-lsp/releases",
+    "debugger": "Not available"
+  },
   {
     "name": "zig",
     "full-name": "Zig",

docs/manual-language-docs/lsp-yang.md

@@ -0,0 +1,10 @@
+---
+author: esmasth
+root_file: docs/manual-language-docs/lsp-yang.md
+---
+<!-- markdownlint-disable-file MD041 -->
+## YANG Language Server (yang-lsp) Client
+
+### Configuration
+
+### Known Issues

lsp-mode.el

@@ -190,7 +190,8 @@ As defined by the Language Server Protocol 3.16."
      lsp-sonarlint lsp-tailwindcss lsp-tex lsp-terraform lsp-toml lsp-ttcn3
      lsp-typeprof lsp-v lsp-vala lsp-verilog lsp-vetur lsp-volar lsp-vhdl
      lsp-vimscript lsp-wgsl lsp-xml lsp-yaml lsp-ruby-lsp lsp-ruby-syntax-tree
-     lsp-solidity lsp-sqls lsp-svelte lsp-steep lsp-tilt lsp-trunk lsp-zig lsp-jq)
+     lsp-solidity lsp-sqls lsp-svelte lsp-steep lsp-tilt lsp-trunk lsp-zig lsp-jq
+     lsp-yang)
   "List of the clients to be automatically required."
   :group 'lsp-mode
   :type '(repeat symbol))
@@ -795,6 +796,7 @@ Changes take effect only when a new session is started."
     ("^PKGBUILD$" . "shellscript")
     ("^go\\.mod\\'" . "go.mod")
     ("^settings.json$" . "jsonc")
+    ("^yang\\.settings$" . "jsonc")
     (ada-mode . "ada")
     (ada-ts-mode . "ada")
     (awk-mode . "awk")
@@ -956,7 +958,8 @@ Changes take effect only when a new session is started."
     (jq-ts-mode . "jq")
     (protobuf-mode . "protobuf")
     (nushell-mode . "nushell")
-    (nushell-ts-mode . "nushell"))
+    (nushell-ts-mode . "nushell")
+    (yang-mode . "yang"))
   "Language id configuration.")
 
 (defvar lsp--last-active-workspaces nil
@@ -6033,6 +6036,7 @@ Request codeAction/resolve for more info if server supports."
     (typescript-mode            . typescript-indent-level)          ; Typescript
     (typescript-ts-mode         . typescript-ts-mode-indent-offset) ; Typescript (tree-sitter, Emacs29)
     (yaml-mode                  . yaml-indent-offset)               ; YAML
+    (yang-mode                  . c-basic-offset)                   ; YANG (yang-mode)
 
     (default                    . standard-indent))                 ; default fallback
   "A mapping from `major-mode' to its indent variable.")

mkdocs.yml

@@ -175,6 +175,7 @@ nav:
     - wgsl: page/lsp-wgsl.md
     - XML: page/lsp-xml.md
     - YAML: page/lsp-yaml.md
+    - YANG: page/lsp-yang.md
     - Zig: page/lsp-zig.md
   - Debugging:
       - https://emacs-lsp.github.io/dap-mode