// ai grammer example from:
/ Artifical Intelligence 2nd ed.; Luger, Stubblefield
/ not exactly the intended use....

/ could be done a little more efficiently with ()'s, but
/  this is how they did it.

{Main}
[sentance]

{Define} [sentance]
[nounphrase] [verbphrase]

{Define} [nounphrase]
[noun]
[art] [noun]

{Define} [verbphrase]
[verb]
[verb] [nounphrase]

{Define} [noun]
man
dog

{Define} [verb]
likes
bites

{Define} [art]
a
the