feat: metals の追加

config/nvim/README.md

@@ -31,11 +31,15 @@
 - 共通 grammar runtime は [modules/neovim.nix](/home/rito528/dotfiles/modules/neovim.nix:1) で `NVIM_TREESITTER_RUNTIME_GLOBAL` として配る
 - project 固有 grammar runtime は `templates/*/flake.nix` の `shellHook` で `NVIM_TREESITTER_RUNTIME_PROJECT` として配る
 - Neovim 側は [init.lua](/home/rito528/dotfiles/config/nvim/init.lua:1) で両方を `runtimepath` に追加する
+- 言語固有の LSP 実行環境は、必要に応じて対応する `templates/*/flake.nix` の dev shell が供給する
+- Scala は `templates/seichi-assist/flake.nix` の dev shell で `metals`, `coursier`, `bloop`, `sbt` を揃え、Neovim 側は `nvim-metals` でそれらを利用する
 - parser を追加・削除するときは、この判断軸と実際の template の責務が一致しているかを確認する
 
 ## 変更時の確認
 
 - `.nix` を変えたら `nixfmt` を実行する
 - Home Manager 側の変更は `home-manager build --flake .#testuser` で確認する
 - template 側の変更は対応する devShell が評価できることを確認する
+- Scala の IDE 機能は `seichi-assist` dev shell 内で Neovim を起動した場合だけを保証する
+- Metals 初回起動時は build import や build server 接続に少し時間がかかることがある
 - Treesitter の配布先を変えた場合は、この README と関連ドキュメントも更新する

config/nvim/lua/config/lsp.lua

@@ -0,0 +1,35 @@
+local M = {}
+
+function M.capabilities()
+  local base = vim.lsp.protocol.make_client_capabilities()
+  local ok, blink = pcall(require, "blink.cmp")
+
+  if not ok then
+    return base
+  end
+
+  return blink.get_lsp_capabilities(base)
+end
+
+function M.on_attach(_, bufnr)
+  local map = function(mode, lhs, rhs, desc)
+    vim.keymap.set(mode, lhs, rhs, {
+      buffer = bufnr,
+      silent = true,
+      desc = desc,
+    })
+  end
+
+  map("n", "K", vim.lsp.buf.hover, "LSP Hover")
+  map("n", "gd", vim.lsp.buf.definition, "LSP Definition")
+  map("n", "gD", vim.lsp.buf.declaration, "LSP Declaration")
+  map("n", "gi", vim.lsp.buf.implementation, "LSP Implementation")
+  map("n", "gr", vim.lsp.buf.references, "LSP References")
+  map("n", "<Leader>rn", vim.lsp.buf.rename, "LSP Rename")
+  map({ "n", "v" }, "<Leader>ca", vim.lsp.buf.code_action, "LSP Code Action")
+  map("n", "<Leader>lf", vim.diagnostic.open_float, "Line Diagnostics")
+  map("n", "[d", vim.diagnostic.goto_prev, "Previous Diagnostic")
+  map("n", "]d", vim.diagnostic.goto_next, "Next Diagnostic")
+end
+
+return M

config/nvim/lua/plugins/completion.lua

@@ -13,6 +13,9 @@ return {
       appearance = {
         nerd_font_variant = "mono",
       },
+      sources = {
+        default = { "lsp", "path", "snippets", "buffer" },
+      },
       completion = {
         documentation = {
           auto_show = false,

config/nvim/lua/plugins/lsp.lua

@@ -3,10 +3,18 @@ return {
     "neovim/nvim-lspconfig",
     event = { "BufReadPre", "BufNewFile" },
     config = function()
-      vim.lsp.config("ts_ls", {})
+      local lsp = require("config.lsp")
+      local base_config = {
+        capabilities = lsp.capabilities(),
+        on_attach = lsp.on_attach,
+      }
+
+      vim.lsp.config("ts_ls", base_config)
       vim.lsp.enable("ts_ls")
 
       vim.lsp.config("eslint", {
+        capabilities = base_config.capabilities,
+        on_attach = base_config.on_attach,
         settings = {
           eslint = {
             autoFixOnSave = true,
@@ -15,13 +23,13 @@ return {
       })
       vim.lsp.enable("eslint")
 
-      vim.lsp.config("jsonls", {})
+      vim.lsp.config("jsonls", base_config)
       vim.lsp.enable("jsonls")
 
-      vim.lsp.config("rust_analyzer", {})
+      vim.lsp.config("rust_analyzer", base_config)
       vim.lsp.enable("rust_analyzer")
 
-      vim.lsp.config("taplo", {})
+      vim.lsp.config("taplo", base_config)
       vim.lsp.enable("taplo")
     end,
   },

config/nvim/lua/plugins/scala.lua

@@ -0,0 +1,56 @@
+return {
+  {
+    "scalameta/nvim-metals",
+    ft = { "scala", "sbt", "java" },
+    dependencies = {
+      "nvim-lua/plenary.nvim",
+      "saghen/blink.cmp",
+    },
+    config = function()
+      if vim.fn.executable("cs") ~= 1 and vim.fn.executable("coursier") ~= 1 then
+        return
+      end
+
+      if vim.fn.executable("bloop") ~= 1 then
+        return
+      end
+
+      local lsp = require("config.lsp")
+      local metals = require("metals")
+      local metals_config = metals.bare_config()
+
+      metals_config.capabilities = lsp.capabilities()
+      metals_config.init_options = vim.tbl_deep_extend("force", metals_config.init_options or {}, {
+        statusBarProvider = "on",
+      })
+      metals_config.settings = {
+        showImplicitArguments = true,
+        showInferredType = true,
+      }
+      metals_config.on_attach = function(client, bufnr)
+        local map = function(mode, lhs, rhs, desc)
+          vim.keymap.set(mode, lhs, rhs, {
+            buffer = bufnr,
+            silent = true,
+            desc = desc,
+          })
+        end
+
+        lsp.on_attach(client, bufnr)
+        map("n", "<Leader>mi", "<Cmd>MetalsImportBuild<CR>", "Metals Import Build")
+        map("n", "<Leader>md", "<Cmd>MetalsRunDoctor<CR>", "Metals Doctor")
+        map("n", "<Leader>mr", "<Cmd>MetalsRestartBuild<CR>", "Metals Restart Build Server")
+      end
+
+      local group = vim.api.nvim_create_augroup("nvim-metals", { clear = true })
+
+      vim.api.nvim_create_autocmd("FileType", {
+        group = group,
+        pattern = { "scala", "sbt", "java" },
+        callback = function()
+          metals.initialize_or_attach(metals_config)
+        end,
+      })
+    end,
+  },
+}

templates/seichi-assist/flake.nix

@@ -17,13 +17,16 @@
     {
       devShells.${system}.default = pkgs.mkShell {
         buildInputs = [
+          pkgs.bloop
+          pkgs.coursier
           pkgs.jdk17
           pkgs.sbt
           pkgs.metals
           pkgs.scalafmt
           pkgs.stdenv.cc.cc.lib
         ];
         shellHook = ''
+          export JAVA_HOME="${pkgs.jdk17}"
           export NVIM_TREESITTER_RUNTIME_PROJECT="${treesitterRuntime}"
           export LD_LIBRARY_PATH="${pkgs.stdenv.cc.cc.lib}/lib''${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}"
         '';