Time flies like an arrow.
Fruit flies like a banana.
- Groucho Marx

I actually have a plan on how to handle context, but that particular
sentence is not imperative in the second sense that you provided.
Since I'm narrowing the scope of sentence types down to imperative,
that helps eliminate _some_ ambiguous situations.   Indeed, most
languages (including programming) are somewhat sensitive to context.

For example, the Java "sentence":
s+=10;

could mean "Increase the int 's' by 10.", or "append '10' to the
String 's'".  It could even be an error if "s" isn't numeric or a
String.

The only reason that isn't considered a problem in Java, is that its
"easy" to determine the context of a statement (scoping rules are
specific and well-defined).  On the other hand, "Get the other key"
depends on context that would be harder to model in a computer.
Especially after a few interactions...

"You see a red key and a blue key."
Look at the red key
"The key is red."
Look at the other key
"The other key is blue."
Get the other key.  <-- Does other point to the other other key, or to
the original other key?

Its been my experience with interactive fictions that the sentence
interpreters tend to need you to be very specific.  I'm sure there are
some out there that have forms of context handling, but I want to
experiment on my own to see how I would go about it.

Originally, I think contextual information will have to be provided by
the world-view designer, with a little help about the "obvious"
context.  Eventually, if the imperative sentence parser becomes good
enough, I would consider expanding the scope of it so that the parser
understood other types of sentences, and could glean information about
the current context simply by the descriptions involved.

And if it is an observation by an surrealist, "time" is an adjective,
"flies" is a noun, "like" is a verb, and "an arrow" is the direct object.

Here's a worse one: "It's a pretty little girls school". I count six
parsings.

Actually, the parser can give a set of all possible parsings, and the
model could determine which makes the most sense based on the current
context.

Yes, the world model is an important part of the interactive fiction.
Its also the easier part to handle in my opinion.  The reason its
easier is that you can limit the world model in ways that you can't
limit what the human will type (without given them an express set of
allowable inputs).  When you come across an ambiguous statement, you
can do one of several things, including asking for clarification or
making a best guess based on current context.

No project or product is finished until its end-of-lifed.  And at that
point, its only finished in the sense of its mortality. :-)  I'm glad
someone else sees my point of view on this.

Do you mean the Visitor pattern? Or is this some reference to
something I don't yet know?

*gulp* :-)

Thanks,
Daniel.