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true-list type specifier
- To: NGALL@BBNG.ARPA
- Subject: true-list type specifier
- From: "Scott E. Fahlman" <Fahlman@C.CS.CMU.EDU>
- Date: Sun, 20 Apr 1986 22:18:00 -0000
- Cc: common-lisp@SU-AI.ARPA
- In-reply-to: Msg of 20 Apr 1986 12:48-EST from NGALL at G.BBN.COM
- Sender: FAHLMAN@C.CS.CMU.EDU
You're wrong here. The term "list" already means what you want
to call a "true list". See the definition on page 26.
No, you're wrong here. On pg. 27 it says: "The Lisp data type LIST is
taken to mean the union of the CONS and NULL data types, and therefore
encompasses both true lists and dotted lists."
OK, now that you mention it, the statement at the bottom of page 27
seems to be more clearly applicable LIST as a type-specifier than the
definition on page 26.
I wonder if any exisitng code would break if we were to define the List
type-specifier to mean "true list"? Implementations would then be free
to use a null test instead of a consp test, though consp would also be
legal. My guess is that some implementations follow this convention
already, even though page 27 seems to label this an error.