xgreenFIGURE 112. "Will you please stack up both of the red blocks and either a green cube or a
pyramid?" [Adapted from Terry Winograd, Understanding Natural Language, p. 12.]
Dr. Tony Earrwig: The result of understanding these sentences is the creation
of new procedures within SHRDLU for deducing whether you own some-
thing.- Eta Din: do i own the box?
SHRDLU: NO.
Dr. Tony Earrwig: The box supports whatever it contains, including a
pyramid. - Eta Din: do i own anything in the box?
SHRDLU: YES, TWO THINGS: THE BLUE BLOCK AND THE BLUE
PYRAMID. - Eta Din: will you please stack uJ> both of the red blocks aDd either a
green cube or a pyramid? [Refer to Fig. 112.]
SHRDLU: OK.
Dr. Tony Earrwig: Logical connectives, such as "and", "or", "either", etc. are
handled in both the grammar and semantics. A command is executed even if
it looks like a question. The.command is carried out by the following series of
steps: SHRDLU puts a green cube on the large red block (it chooses the
green cube with nothing on it), then removes the small pyramid from the
little red cube, so that it can use that cube to complete the stack as specified.
SHRDLU, Toy of Man's Designing 589