Refactor Statement

[davepagurek]

Statement currently just adds a semicolon. However, there are more types of statements that don't do this (e.g. if statements.) They all do not have a return value. What's the best way to encode this as a TypeScript type?

Typescript doesn't really do nominal types, only structural types, so if we make a Statement interface that is the exact same as the SyntaxNode interface, then we could pass in an arbitrary SyntaxNode anywhere we want a Statement, which isn't what we want.

If there are a fixed number of statement types, we could maybe do something like:

type Statement = If | While | DoWhile | For | Line;

(also is there a better name for Line?)

Thoughts?