How to turn a Parser<I, Parser<I, O>> into a Parser<I, O>?

[davnavr]

I'm creating a parser for a toy language I'm working on, and I have a HashMap<&'static str, BoxedParser<_, _, _>> that I want to use to select a parser based on some prior keyword that was already parsed. Other libraries such as combine offer a then function or in FParsec for the F# language, the >>= operator to select a parser based on input. Aside from trying to figure out how to use custom, is what I'm trying to do currently possible?

Thanks!

[zesterer]

Yes, this is now permitted. The master branch contains the Parser::then_with combinator that should do what you want. It is due for inclusion in the next stable release.