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From: mpjames@rohmhaas.com (Mike James)
Subject: Re: Where is atom? in MIT Scheme?
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References: <RISINGER.95Apr30110725@netcom20.netcom.com> <3o2mff$svu@sundog.tiac.net> <WAND.95May1165547@delphi.ccs.neu.edu>
Date: Sat, 6 May 1995 02:28:30 GMT
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In article <WAND.95May1165547@delphi.ccs.neu.edu>,
   wand@delphi.ccs.neu.edu (Mitchell Wand) wrote:
>>>>>> In article <3o2mff$svu@sundog.tiac.net>, gary@wheel.tiac.net (Gary D. 
Duzan) writes:
>
>Gary> In article <RISINGER.95Apr30110725@netcom20.netcom.com>,
>Gary> James A. Risinger <risinger@netcom20.netcom.com> wrote:
>Gary> =>I am using MIT Scheme, and atom? is not defined in the implementation
>Gary> =>that I am using.  Does anyone know why this is?  I am using Schematic
>Gary> =>on a NeXT, Microcode 11.59.  
>Gary> =>
>Gary>    Just checked and mine doesn't have it either. You can always just
>Gary> (define atom? (lambda (x) (not (pair? x)))). My Scheme reference gives
>Gary> that as a definition, anyway.
>
>Gary>                                       Gary D. Duzan
>Gary>                          Humble Practitioner of the Computer Arts
>
>MIT Scheme probably doesn't have  atom?  because  atom?  isn't a standard
>Scheme procedure, which is because Scheme doesn't have a data type of atoms. 
>
>You probably meant  symbol?  instead.
>
>Look at http://www.cs.indiana.edu/scheme-repository/doc.standards.html, which
>has links to the official reports, including the R4RS document (
>ftp://ftp.cs.indiana.edu/pub/scheme-repository/doc/standards/r4rs.ps.gz
>)
>--Mitch 
>
>Mitchell Wand				      Internet: wand@ccs.neu.edu
>College of Computer Science, Northeastern University
>360 Huntington Avenue #161CN, Boston, MA 02115     Phone: (617) 373 2072
>World Wide Web: http://www.ccs.neu.edu/home/wand   Fax:   (617) 373 5121
>
>
>
>
>
	Yes, MIT scheme doesn't have atom? in fact.  However, it is certainly 
listed in Abelson and Sussman's book, "Structure and Interpretation of 
Computer Programs" as a primitive predicate, which is why I went looking for 
it also.
