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- To: steele@CMU-CS-C
- Subject: ENDP
- From: Scott E. Fahlman <Fahlman@CMU-CS-C>
- Date: Fri, 27 May 1983 02:49:00 -0000
- Cc: common-lisp@su-ai
In the DTYPES chapter (May 10) you say that functions that require lists
expect to be given true lists, but that "whether a function that
requires a true list will behave reasonably when given a dotted list
depends on the implementation".
I agree with the sentiment, but I would like to propose a rewording:
"It is an error to pass a dotted list to a function that is specified as
requiring a list argument. Implementors are encouraged to check for
this error by using ENDP (ref) to check for the end of the loop.
However, since this test is often part of an inner loop, it must be
efficient. Some implementations may choose to use ATOM for such tests,
quietly ignoring any non-null terminating atom."
Or something like that. All of our implementations are reasonable, but
on a Vax there's a limit to how reasonable you can be.