feat(langauges): Configure the haskell language server

lua/plugins/languages/haskell.lua

@@ -0,0 +1,46 @@
+return {
+  'mrcjkb/haskell-tools.nvim',
+  version = '^4',
+  lazy = false, -- This plugin is already lazy
+	cond = vim.fn.executable("haskell-language-server") ~= 0,
+	init = function()
+		vim.api.nvim_create_autocmd("LspAttach", {
+			group = vim.api.nvim_create_augroup("UserLspConfig", {}),
+			callback = function(ev)
+				local client = vim.lsp.get_client_by_id(ev.data.client_id)
+
+				if client ~= nil and client.name == "haskell-tools.nvim" then
+					local ht = require('haskell-tools')
+					local bufnr = ev.buf
+
+					local map = function(keys, action, desc)
+						local opts = { noremap = false, silent = true, buffer = bufnr }
+						if desc ~= nil then
+							opts.desc = desc
+						end
+						vim.keymap.set("n", keys, action, opts)
+					end
+
+					-- haskell-language-server relies heavily on codeLenses,
+					-- so auto-refresh (see advanced configuration) is enabled by default
+					map('<space>lcl', vim.lsp.codelens.run, nil)
+
+					map('<space>lhs', ht.hoogle.hoogle_signature, "Hoogle search for the type signature of the definition under the cursor")
+
+					map('<space>lea', ht.lsp.buf_eval_all, "Evaluate all code snippets")
+
+					map('<leader>lrr', ht.repl.toggle, "Toggle a GHCi repl for the current package")
+
+					-- Toggle a GHCi repl for the current buffer
+					map('<leader>lrb', function()
+					  ht.repl.toggle(vim.api.nvim_buf_get_name(0))
+					end, nil)
+
+					map('<leader>lrq', ht.repl.quit, "Quit the current GHCi repl")
+
+					vim.notify("Just done seting up hls")
+				end
+			end
+		})
+	end,
+}