From simon.urbanek at r-project.org  Wed Mar  3 17:49:50 2010
From: simon.urbanek at r-project.org (Simon Urbanek)
Date: Wed, 3 Mar 2010 11:49:50 -0500
Subject: [Rd] What is pairlist in R-ints.pdf?
In-Reply-To: <48413fa11003030829t42b53499je20df27ec41d2e05@mail.gmail.com>
References: <48413fa11003030829t42b53499je20df27ec41d2e05@mail.gmail.com>
Message-ID: <310330E0-C213-4A07-9791-151C3BB4DBC9@r-project.org>


On Mar 3, 2010, at 11:29 , blue sky wrote:

> R-ints.pdf mentions pairlist with the reference to mit-scheme.
> However, it is not clear to me what 'pairlist' exactly refers to, as  
> I don't find the definition for it. Does a 'pairlist' in R  
> equivalent to a pair or a list (which is essentially a pair whose  
> cdr is a list) in mit-scheme?
>

pairlist is short for "dotted pair list" (see ?pairlist) which is a  
syntax for specifying linked lists as ( CAR . CDR ). Since the term  
"list" has a different meaning in R, using just "list" would be  
ambiguous (in the current R lists are implemented as generic vectors,  
not as linked lists).

Cheers,
Simon



[Rd] What is pairlist in R-ints.pdf?
Simon Urbanek