This paper gives the best algorithm I know of, and a sketch of its complexity: http://dinhe.net/~aredridel/.notmine/PDFs/Parsing/SPIEWAK,%20Daniel%20(2010)%20-%

This paper gives the best algorithm I know of, and a sketch of its complexity: http://dinhe.net/~aredridel/.notmine/PDFs/Parsing/SPIEWAK,%20Daniel%20(2010)%20-%20Generalized%20Parser%20Combinators.pdf http://dinhe.net/~aredridel/.notmine/PDFs/Parsing/SPIEWAK,%2....