[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
ENDP
- To: common-lisp@su-ai
- Subject: ENDP
- From: David A. Moon <Moon%SCRC-TENEX%MIT-MC@SU-DSN>
- Date: Fri, 27 May 1983 03:56:00 -0000
- In-reply-to: The message of 26 May 83 22:49-EDT from Scott E. Fahlman <Fahlman at CMU-CS-C>
I like Scott's wording better. However, I surmise that the use of the
vague expression "whether ... will behave reasonably ... depends on the
implementation" was intended to convey the idea that some implementations
will use a NULL check (rather than an ATOM check) and hence will behave
most unreasonably, cdr'ing off into randomness, when given a dotted
list. Of course this is discouraged, but the manual should say explicitly
whether it is allowed or forbidden. To summarize:
1. ENDP check (or NULL check plus always-error-checking CDR)
Error if given a dotted list and end of it reached
2. ATOM check
Dotted list simply behaves like an undotted one
3. NULL check
Dotted list causes unpredictable behavior.