Predicates of writtenPAM
Finally there are the predicates.
line? returns if its argument is a line (a drawline or a
character or a textline) and .
equal? is the general equality test for text-graphic objects. In
order to be equal, two objects must appear the same visually
irrespective of their location, orientation or size in relation to each
other. And, if the two objects are characters, textlines, or patterns,
then they must also have parallel tree structures.
identical? is the location, orientation and size dependent
equality test. Identical objects not only appear the same and are built
the same, they are also located, oriented and sized to each other
exactly; two identical objects displayed simultaneously will be
precisely on top of each other (all their lines will be coincident).