These are generator functions that all create a subroutine closure which
produce pairs of ( value, position ) until their source is exhaused, and undef
when no values remain.
filter_regexp ( REGEXP, CODEREF )
Given a coderef matching the signature given for Algorithm::RabinKarp,
this method will create a generator that skips all characters that match a
stream_fh ( FileHandle )
Iterates across values in a file handle.
stream_string ( $scalar )
Iterates across characters in a string.