refactor(commands): use table to map commands to implementations (#6)

plugin/rocks.lua

@@ -1,23 +1,40 @@
--- Set up the Rocks autocommand
+-- Set up the Rocks user command
 
-local function rocks(opts)
-    local args = opts.fargs
-    local operations = require("rocks.operations")
+---@type { [string]: fun(args:string[]) }
+local command_tbl = {
+    update = function(_)
+        require("rocks.operations").update()
+    end,
+    sync = function(_)
+        require("rocks.operations").sync()
+    end,
+    install = function(args)
+        if #args == 0 then
+            vim.notify("Rocks install: Called without required package argument.", vim.log.levels.ERROR)
+            return
+        end
+        local package, version = args[1], args[2]
+        require("rocks.operations").add(package, version)
+    end,
+}
 
-    if args[1] == "update" then
-        operations.update()
-    elseif args[1] == "sync" then
-        operations.sync()
-    elseif args[1] == "install" then
-        operations.add(args[2], args[3])
+local function rocks(opts)
+    local fargs = opts.fargs
+    local cmd = fargs[1]
+    local args = #fargs > 1 and vim.list_slice(fargs, 2, #fargs) or {}
+    local command = command_tbl[cmd]
+    if not command then
+        vim.notify("Rocks: Unknown command: " .. cmd, vim.log.levels.ERROR)
+        return
     end
+    command(args)
 end
 
 vim.api.nvim_create_user_command("Rocks", rocks, {
     nargs = "+",
     desc = "Interacts with currently installed rocks",
     complete = function(arg_lead, cmdline, _)
-        local commands = { "update", "sync", "install" }
+        local commands = vim.tbl_keys(command_tbl)
 
         if cmdline:match("^Rocks%s+%w*$") then
             return vim.iter(commands)