[r6rs-discuss] [Formal] Add symbol=? and boolean=?

[John Cowan]

Per Bothner scripsit:

> [I]t seems that if you were to design a language from scratch you
> probably make a clearer distinction between values and objects.

Actually the distinction is quite clear: something is a value
if it's immutable, and not a value if it is mutable.  Henry Baker
nailed this with his EGAL predicate, which is value equality
on immutable things and object identity on mutable things: see
http://home.pipeline.com/~hbaker1/ObjectIdentity.html .
(This is a very interesting paper, and I recommend that anyone
interested in the semantics of equality predicates read it.)

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