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Re: SRFI-5 breaks original let?

To: scsh-users@scsh.net
Subject: Re: SRFI-5 breaks original let?
From: Martin Gasbichler <gasbichl@informatik.uni-tuebingen.de>
Date: Wed, 06 Oct 2004 13:39:58 +0200
List-id: <scsh-users.list-id.scsh.net>
Andreas Bernauer <andreas.bernauer@gmx.de> writes:

> Gary Baumgartner wrote in June:
>> In 0.6.6, opening srfi-5 seems to break some original uses of let:
>> 
>> > (let () 'hi)
>> 'hi
>> > ,open srfi-5
>> Load structure srfi-5 (y/n)? y
>> [srfi-5 /usr/lib/scsh/srfi/srfi-5.scm]
>> > (let () 'hi)
>> 
>> Warning: invalid expression
>>          ()
>> 
>> Error: undefined variable
>>        standard-let
>>        (package srfi-5)
>> 
>> 
>> The file scheme/srfi/srfi-5.scm in the source distribution rewrites let
>> to standard-let, but there is no standard-let defined. A fix seems to be
>> to change
>> 
>> (define-structure srfi-5 (export (let :syntax))
>>   (open (modify scheme-level-2 (hide let)))
>> 
>> to
>> 
>> (define-structure srfi-5 (export (let :syntax))
>>   (open (modify scheme-level-2 (rename (let standard-let)) (hide let)))
>> 
>> in scheme/more-packages.scm.
>> 
>> I'm not familiar with the details of the structure system, so I may not
>> be opening the package correctly. Furthermore, if it is a bug I'm unclear
>> whether (hide let) should be left in.
>
> Has this been adressed by anybody in the meanwhile? 

No, strange, I don't even remeber Gary's email. 

> As far as I can see, this is a bug (either in scsh or in srfi-5's
> example implementation, depending on how you look at it) and Gary's
> proposal seems to correct it.

Yes, even though the HIDE clause is superfluous. I'll fix it in CVS
and in the Scheme 48 sources.

-- 
Martin

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