Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!ames!elroy!ucla-cs!pierce
From: pierce@lanai.cs.ucla.edu (Brad Pierce)
Newsgroups: comp.lang.scheme
Subject: Re: unspecified-object
Message-ID: <24244@shemp.CS.UCLA.EDU>
Date: 25 May 89 06:20:05 GMT
References: <24169@shemp.CS.UCLA.EDU> <8905241845.AA02829@zohar>
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Reply-To: pierce@cs.ucla.edu (Brad Pierce)
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Organization: UCLA Computer Science Department
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In article <8905241845.AA02829@zohar> jar@zurich.ai.mit.edu writes:

>It doesn't make sense to specify that the object to be returned should
>be unspecified.  It seems to me that if some specific object is to be
>specified, then it should be a specific object, not an unspecific one.
>Besides, if we specify what object should be returned, then that
>object will no longer be unspecified.

When a procedure is applied to valid input and the result is unspecified,
valuable information is lost.  I am suggesting removing the possibility of
leaving unspecified the result of valid procedure applications. I am also
suggesting that there be a special object which represents the important
information which is currently discarded. Practical benefits aside, I 
simply find it aesthetically unpleasant to pass around values which have no
information content, when an alternative approach is possible.

-- Brad