Sadly I think Rust's way is the best one in the long term even if it's not very user friendly. There are a lot of problems with the FreeBASIC syntax, my comment was mostly wishful thinking. As other user has said in a reply to my comment, you can't beat the level of control Rust's syntax provides and that's what most people writing assembly would want. You are also right that a proper asm parser would be difficult to maintain due to the amount of architectures Rust has to support.