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From: grante@reddwarf.rosemount.com (Grant Edwards)
Subject: Property list question
Message-ID: <1994Oct14.225950.28456@rosevax.rosemount.com>
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Date: Fri, 14 Oct 1994 22:59:50 GMT
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In Dybvig's book "The Scheme Programming Language" section 5-7
describes property lists and the getprop and putprop procedures.
These are listed as extensions (which I assume are provided by Chez
Scheme - since the foreword states the examples were done using Chez
Scheme).

The book states that property lists belong to "symbols."  The text is
quite explicit that the argument must be a symbol, and all examples
are shown with quoted symbols.

Do the properties in fact belong to the symbol and not to the object
to which the symbol is bound?

This would seem to imply that you can assign properties to an unbound
symbol and that doing a set! on a symbol would not change it's
property list.

This doesn't sound very useful to me, but maybe I'm missing something.

--

I haven't been very pleased with the book in general - the sections
describing the various procedures do not specify what is required by
R4RS as part of the core language, what is defined but not required,
and what is an extension to Chez Scheme.  There is a summary at the
end of the book which lists which are essention, optional and
extension forms, but it took me a while to find that, and it's a bit
difficult to constantly flip back and forth.

Considering the price ($40US for a softback book the size of K&R's
"The C Programming Language") I've decided it wasn't a good buy.

--
Grant Edwards                                 |Yow!  I brought my BOWLING
Rosemount Inc.                                |BALL - and some DRUGS!!
                                              |
grante@rosemount.com                          |
