Description

after(expr) succeeds if the expr sub-expression would match at the current position minus N in the sequence, where N is the width of expr. expr is not included in the match. For instance, after("foo") succeeds if we are after a "foo". Look-behind assertions can be negated with the bit-complement operator.

	Note
	after(expr) is equivalent to the perl (?<=...) extension. ~after(expr) is a negative look-behind assertion, equivalent to the perl (?<!...) extension.