Final exercise: Modifying the language processor

I have made a few changes to the language system from last week. The new version can be found in the same place the old version was.

~tvandrun/Public/cs394/language3.sml

The new version allows for noun phrases to be modified with prepositional phrases, for example, "The tree of the field seemed important."

The first thing you should do is merge this with what you did last week.

Now, here are the changes you should make to this:

• Redesign nouns to model noun morphology, as we did with verbs (you began working on this last week)
• Write a function makePlural() that takes a sentence and converts it to a string except that the subject is made plural and the verb is inflected to be present tense and to agree with the plural subject.
• Write a function printWithPossessives() that takes a sentence and converts it to a string except that all cases where a noun phrase is modified by a prepositional phrase beginning with of, we instead make the object of that preposition to be a possessive noun modifying the main noun phrase. For example, "A big tree of the field" becomes "the field's big tree". Notice that the article of the enclosing noun phrase is not printed.