possibly : ('a -> 'b * 'a) -> 'a -> 'b list * 'a

Attempts to parse, returning empty list of items in case of failure.

If p is a parser, then possibly p is another parser that attempts to parse with p and if successful returns the result as a singleton list, but will return the empty list instead if the core parser p raises Noparse.

Never fails.

This is one of a suite of combinators for manipulating ``parsers''. A parser is simply a function whose OCaml type is some instance of :('a)list -> 'b * ('a)list. The function should take a list of objects of type :'a (e.g. characters or tokens), parse as much of it as possible from left to right, and return a pair consisting of the object derived from parsing (e.g. a term or a special syntax tree) and the list of elements that were not processed.

++, |||, >>, a, atleast, elistof, finished, fix, leftbin, listof, many, nothing, rightbin, some.