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From: krulwich@ils.nwu.edu (Bruce Krulwich)
Newsgroups: comp.lang.scheme
Subject: Re: Making language constructs out of glue  (was Re: What is a Scheme?)
Message-ID: <1478@anaxagoras.ils.nwu.edu>
Date: 23 Aug 90 20:50:48 GMT
References: <JINX.90Aug22122411@chamarti.ai.mit.edu> <9008221644.aa03978@mc.lcs.mit.edu> <1990Aug23.020704.19833@rice.edu> <1475@anaxagoras.ils.nwu.edu>
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Reply-To: krulwich@ils.nwu.edu (Bruce Krulwich)
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In-reply-to: krulwich@ils.nwu.edu (Bruce Krulwich)

In article <1475@anaxagoras.ils.nwu.edu>, I wrote:

>The typical example of this type of thing is replacing booleans and
>conditionals with LAMBDA's and calls, with:
>
>        #T                             => (lambda (t-val f-val) t-val)
>        #F                             => (lambda (t-val f-val) f-val)
>        (IF <bool> <t-val> <nil-val>)  => (<bool> <t-val> <f-val>)


When writing this I forgot to wrap the (LAMBDA () ...)'s around <t-val> and
<f-val> in the IF transformation, and add evaluation of the appropriate 
thunk in the #T and #F procedures.  This is necessary in order to have only 
the appropriate value evaluated.


Bruce Krulwich
Institute for the Learning Sciences