recursive descent parser and functional programming

Question

So lately I have been working on writing a simple compiler to better understand compiler concepts. Being a diligent reader of stackoverfolow, it seems there is a consensus that

Answer 1

A simpler answer than the other good answers:

A parser in a function language takes a token stream into a parse tree and the rest of the token stream. That is, it has type

 token list -> ast * token list

A recursive decent parser usually have a large number of functions that of this type which eats the token stream and then builds a little part of the parse tree. By calling these recursively (recursive decent) -- you get what you want.

The next step up is to use higher order parsers: parsers operating on other parsers. This is what parser combinator libraries do. Perhaps you could start with a simple recursion scheme and then upgrade it to parser combinators.