Scala

Install Syntax Highlighting

:TSInstall scala

The support for Scala 3 like syntax is limited.

Install Language Server

To get scala LSP support working in Lunarvim, first you need to do the prerequisites listed here

Then use coursier to install the metals language server so that it is available on your PATH:

coursier install metals

Also, you can install the scala formatter

coursier install scalafmt

Configure Lunarvim

Create a file called ~/.config/lvim/lua/user/metals.lua:

local M = {}

M.config = function()
  local lvim_lsp = require("lvim.lsp")
  local metals_config = require("metals").bare_config()
  metals_config.on_init = lvim_lsp.common_on_init
  metals_config.on_exit = lvim_lsp.common_on_exit
  metals_config.capabilities = lvim_lsp.common_capabilities()
  metals_config.on_attach = function(client, bufnr)
    lvim_lsp.common_on_attach(client, bufnr)
    require("metals").setup_dap()
  end
  metals_config.settings = {
    superMethodLensesEnabled = true,
    showImplicitArguments = true,
    showInferredType = true,
    showImplicitConversionsAndClasses = true,
    excludedPackages = {},
  }
  metals_config.init_options.statusBarProvider = false
  vim.api.nvim_create_autocmd("FileType", {
    pattern = { "scala", "sbt", "java" },
    callback = function() require("metals").initialize_or_attach(metals_config) end,
    group = vim.api.nvim_create_augroup("nvim-metals", { clear = true }),
  })
end

return M

Add the following to your config.lua

lvim.plugins = {
    {
      "scalameta/nvim-metals",
      config = function()
        require("user.metals").config()
      end,
    },
}

dap.configurations.scala = {
  {
    type = "scala",
    request = "launch",
    name = "Run or Test Target",
    metals = {
      runType = "runOrTestFile",
    },
  },
  {
    type = "scala",
    request = "launch",
    name = "Test Target",
    metals = {
      runType = "testTarget",
    },
  },
}

When you open the first scala file, you should run :MetalsInstall in order to complete the plugin installation.

To debug scala program, make sure that dap is activated:

lvim.builtin.dap.active = true

Any Lunarvim builtin debug commands, which could be displayed by pressing <leader> d, is supported.

Supported formatters

In most cases, isn't necessary enable the scalafmt formatter, this is already integrated with metals to format on save creating a .scalafmt.conf file in your project root, see more here

• scalafmt