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- To: firstname.lastname@example.org (Christopher Owens)
- Subject: Re: remove
- From: kab (Kim Barrett)
- Date: Tue, 24 Nov 92 10:13:03
- Cc: info-mcl
> > On the other hand, Common Lisp, the Manual, states that "the result [of
> > remove] is a copy of the input sequence." If you return part of the
> > original list, then you change the contract of the function. Sometimes
> > one uses remove and requires a totally new list. One must be careful
> > about "efficiency".
> I was just about to post exactly this response until, in a stunning
> (for me) display of scholarship, I read a page further in the
> reference and discovered what seems to me like an inconsistency in the
> defined semantics of the function. (CLtL2, pg 400):
> "The result of REMOVE may share with the argument; a list result may
> share a tail with an input list, and the result may be eq to the
> input sequence if no elements need to be removed."
The use of the phrase "is a copy" is only intended to emphasize the immediately
preceding statement that the function is non-destructive. The dpANS uses
wording that avoids this bit of confusion.