Hacker News Reader

Pausing is very straightforward with bottom up algorithms like GLR. The entire state of the parse is stored in an explicit stack data structure, as opposed to implicitly in the program's call stack as with top-down algorithms. So resuming the parse is as simple as resuming the parse loop using a previously-stored stack.

I think this is a bit of an orthogonal issue. Inversion of control is a problem that can be solved at the language level with coroutines / continuations / threads / etc without forcing you to choose a special type of algorithm.

Earley parsing can handle asynchronous input just fine.