Implicit contracts

[Rob MacLachlan <RAM@CMU-CS-C.ARPA>]

    I think that the specification of a language by implementation as
implied by Dyer's message is an extremely bad idea.  If it is legal to
depend on any possible behavior of a function then it becomes
impossible to ever change any function because someone might depend on
a particular idiosyncratic behavior.

    It seems to me that the best approach in Common Lisp is to have
that manual describe every important behavior of an operation, and for
any code which depends on something not guaranteed by the manual to be
considered erroneous.

    As far as assuring agreement with the manual, I think that the
best solution would be to have a comprehensive validation suite, or
lacking that, a number of large portable applications.

  Rob