property value: n. (of a property indicator on
a property list)
the object associated with the property indicator
on the property list.
purports to conform: v. makes a good-faith claim of conformance.
This term expresses intention to conform, regardless of whether the
goal of that intention is realized in practice.
For example, language implementations have been known to have bugs,
and while an implementation of this specification with bugs
might not be a conforming implementation, it can still
purport to conform. This is an important distinction in
certain specific cases; e.g., see the variable *features*.