PR Stanley writes:

Hi taken from ch.8.3 in the Hutton book: "Whereas return v always succeeds, the dual parser failure always fails regardless of the contents of the input string:" The dual parser failure?

It's a question of how you parse the phrase "dual parser failure". The name of the parser is "failure" and it is the dual (roughly meaning "opposite") of the parser "return". -- Jón Fairbairn Jon.Fairbairn@cl.cam.ac.uk