Most programs that use b() parse only one language and therefore contain
only one b() parser. But what if you want to parse more than one language
with the same program? Since b() constructs em(class) rather than a
em(parsing function), this problem can easily be solved: simply define your
second (third, fourth, ...) parser class, each having its own unique
class-name, using the tt(%class-name) directive, and construct parser objects
of each of the defined classes.
