Add the concept of commands to the world and executing them

pkg/game/command.go

@@ -0,0 +1,23 @@
+package game
+
+import "github.com/google/uuid"
+
+// A command is simply a function that acts on the a given instance in the world
+type Command func() error
+
+// CommandMove will move the instance in question
+func (w *World) CommandMove(id uuid.UUID, vec Vector) Command {
+	return func() error {
+		// Move the instance
+		_, err := w.MovePosition(id, vec)
+		return err
+	}
+}
+
+// CommandSpawn
+// TODO: Two spawn commands with the same id could trigger a fail later on, we should prevent that somehow
+func (w *World) CommandSpawn(id uuid.UUID) Command {
+	return func() error {
+		return w.Spawn(id)
+	}
+}