Nice! It doesn't look like the AST contains positioning information, so it can't be corrolated with the source code. It would be nice if this supported or enabled eventually.
@fkling Sweet, thanks! I've started on a PR adding positional information to the AST here but will need some help from the lib author. Will create a new PR here to add support once that's done
Adds support for ASTs generated by http://mathjs.org