Sounds good to me. But there are a lot of authoring tools around that already do all the lexical analysis, parsing and pattern matching for you. You don't need to write something from scratch, unless you really want to.
I’ve been tempted to port a pure-python lexer&parser (PLY) over to Godot’s gdscript. God have mercy on me, I probably will do that, knowing that I’ll never finish in time! :]