Merge pull request #860 from NotAShelf/lsp-api

neovim/lsp: expose low-level API

lib/languages.nix

@@ -1,10 +1,11 @@
-# From home-manager: https://github.com/nix-community/home-manager/blob/master/modules/lib/booleans.nix
 {lib}: let
   inherit (builtins) isString getAttr;
   inherit (lib.options) mkOption;
-  inherit (lib.types) bool;
+  inherit (lib.types) listOf bool str submodule attrsOf anything either nullOr;
   inherit (lib.nvim.attrsets) mapListToAttrs;
+  inherit (lib.nvim.types) luaInline;
 in {
+  # TODO: remove
   diagnosticsToLua = {
     lang,
     config,
@@ -32,4 +33,48 @@ in {
       type = bool;
       description = "Turn on ${desc} for enabled languages by default";
     };
+
+  lspOptions = submodule {
+    freeformType = attrsOf anything;
+    options = {
+      enable = mkOption {
+        type = bool;
+        default = true;
+        description = "Whether to enable this LSP server.";
+      };
+
+      capabilities = mkOption {
+        type = nullOr (either luaInline (attrsOf anything));
+        default = null;
+        description = "LSP capabilitiess to pass to lspconfig";
+      };
+
+      on_attach = mkOption {
+        type = nullOr luaInline;
+        default = null;
+        description = "Function to execute when an LSP server attaches to a buffer";
+      };
+
+      filetypes = mkOption {
+        type = nullOr (listOf str);
+        default = null;
+        description = "Filetypes to auto-attach LSP in";
+      };
+
+      cmd = mkOption {
+        type = nullOr (listOf str);
+        default = null;
+        description = "Command used to start the LSP server";
+      };
+
+      root_markers = mkOption {
+        type = nullOr (listOf str);
+        default = null;
+        description = ''
+          "root markers" used to determine the root directory of the workspace, and
+          the filetypes associated with this LSP server.
+        '';
+      };
+    };
+  };
 }

modules/neovim/init/default.nix

@@ -5,6 +5,7 @@
     ./debug.nix
     ./diagnostics.nix
     ./highlight.nix
+    ./lsp.nix
     ./spellcheck.nix
   ];
 }

modules/neovim/init/lsp.nix

@@ -0,0 +1,82 @@
+{
+  config,
+  lib,
+  ...
+}: let
+  inherit (builtins) filter;
+  inherit (lib.modules) mkIf mkMerge mkDefault;
+  inherit (lib.options) mkOption;
+  inherit (lib.types) attrsOf;
+  inherit (lib.strings) concatLines;
+  inherit (lib.attrsets) mapAttrsToList attrNames filterAttrs;
+  inherit (lib.generators) mkLuaInline;
+  inherit (lib.nvim.languages) lspOptions;
+  inherit (lib.nvim.dag) entryAnywhere;
+  inherit (lib.nvim.lua) toLuaObject;
+
+  cfg = config.vim.lsp;
+
+  lspConfigurations =
+    mapAttrsToList (
+      name: value: ''
+        vim.lsp.config["${name}"] = ${toLuaObject value}
+      ''
+    )
+    cfg.servers;
+
+  enabledServers = filterAttrs (_: u: u.enable) cfg.servers;
+in {
+  options = {
+    vim.lsp.servers = mkOption {
+      type = attrsOf lspOptions;
+      default = {};
+      example = ''
+        {
+          "*" = {
+            root_markers = [".git"];
+            capabilities = {
+              textDocument = {
+                semanticTokens = {
+                  multilineTokenSupport = true;
+                };
+              };
+            };
+          };
+
+          "clangd" = {
+            filetypes = ["c"];
+          };
+        }
+      '';
+      description = ''
+        LSP configurations that will be managed using `vim.lsp.config()` and
+        related utilities added in Neovim 0.11. LSPs defined here will be
+        added to the resulting {file}`init.lua` using `vim.lsp.config` and
+        enabled through `vim.lsp.enable` below the configuration table.
+
+        You may review the generated configuration by running {command}`nvf-print-config`
+        in a shell. Please see {command}`:help lsp-config` for more details
+        on the underlying API.
+      '';
+    };
+  };
+
+  config = mkMerge [
+    {
+      vim.lsp.servers."*" = {
+        capabilities = mkDefault (mkLuaInline "capabilities");
+        on_attach = mkDefault (mkLuaInline "default_on_attach");
+      };
+    }
+
+    (mkIf (cfg.servers != {}) {
+      vim.luaConfigRC.lsp-servers = entryAnywhere ''
+        -- Individual LSP configurations managed by nvf.
+        ${concatLines lspConfigurations}
+
+        -- Enable configured LSPs explicitly
+        vim.lsp.enable(${toLuaObject (filter (name: name != "*") (attrNames enabledServers))})
+      '';
+    })
+  ];
+}

modules/plugins/languages/default.nix

@@ -1,4 +1,8 @@
-{lib, ...}: let
+{
+  config,
+  lib,
+  ...
+}: let
   inherit (lib.nvim.languages) mkEnable;
 in {
   imports = [
@@ -47,7 +51,11 @@ in {
   ];
 
   options.vim.languages = {
-    enableLSP = mkEnable "LSP";
+    # LSPs are now built into Neovim, and we should enable them by default
+    # if `vim.lsp.enable` is true.
+    enableLSP = mkEnable "LSP" // {default = config.vim.lsp.enable;};
+
+    # Those are still managed by plugins, and should be enabled here.
     enableDAP = mkEnable "Debug Adapter";
     enableTreesitter = mkEnable "Treesitter";
     enableFormat = mkEnable "Formatting";