[plt-scheme] When does eqv? differ from eq? , from equal?

[Shriram Krishnamurthi]

Using numbers to drive a wedge between EQ? and EQV? doesn't really do
much to persuade me.  I never use EQ? for numbers, only =.  I only use
EQ? when comparing structured (and inevitably mutable) objects, for
which EQ? is a semantically meaningful operation.

Shriram