Understanding aptitude search patterns

[Panayiotis Karabassis <panayk@gmail.com>]

Hi! I am having some trouble understanding aptitude search patterns.

In particular I am confused about what it is that some patterns match:
all versions of a package or a particular version?

?and(A, B) pattern matches a package if A matches some version and B
matches some version of the package. Does it return all versions of the
package regardless of whether they matched?

?narrow(A, B) pattern matches a package if one version matches A and B.
It returns the version(s) that matched A and B simultaneously, correct?

?any-version(?and(A B)) pattern matches a package if one version matches
A and B, like narrow.

But I don't understand how this works. ?and(A B) is a list of package
versions. What does ?any-version do with it?

What about ?any-version(?or(A B)). What does this match? Etc.

I am currently browsing the source code, but I find the terminology too
difficult.

-- 
Best regards,
    Panayiotis Karabassis