Currently if I want to load the antlr4 JS runtime into a constrained environment everything works flalwesly, but there is a small change that I have to monkey-patch on my side each time: the this.readInt.bind(this) call fails because bind doesn't exist.

Since this issue only happens on 2 lines (and all others just work without issue) I thought maybe an alternative solution might help remove this last problem by using a very easy straight-forward replacement of those 2 lines?

Thank you for the great work on this library, it really helps a lot and I am a great fan!