[plt-scheme] question from a newbie regarding the import of a library

Looks good to me.
We write a macro for (run #f (q) ...), which we call (run* (q) ...)
You might want to add it.
... Dan

On Sun, Apr 5, 2009 at 3:23 AM, Jon Loldrup <loldrup at gmail.com> wrote:

> Well it sure does evaluate successfully now, and testing the first 4
> expressions on page 4 in "The Reasoned Schemer" makes them all return the
> same value as the ones in that book. Only thing is, the book doesn't mention
> the definitions of fail and succeed (only that they are longs for #u and
> #s), so I'm not sure whether this solution is some crude hack or the
> official way to do it.
>
> Now this code:
>
> #lang scheme
> (require (planet dfriedman/miniKanren:1:1/minikanren))
> (define succeed (== #t #t))
> (define fail (== #t #f))
> (run #f (q) fail)
> (run #f (q) (== #t q))
> (run #f (q) fail (== #t q))
> (run #f (q) succeed (== #t q))
>
> returns this:
>
> ()
> (#t)
> ()
> (#t)
>
>
> Jon Loldrup
>
>
> 2009/4/5 Ben Goetter <goetter at mazama.net>
>
> Jon Loldrup wrote:
>>
>>>
>>> [...] the third line was taken from the file mktests.scm <
>>> http://kanren.cvs.sourceforge.net/viewvc/kanren/kanren/mini/mktests.scm?revision=1.6&view=markup>
>>> which I think is designed to test a minikanren implementation.
>>>
>> That file tests the particular version of minikanren currently on
>> Sourceforge, which is not the same as the version on PLaneT.  You cannot
>> necessarily mix and match the two.  Still, (run #f (q) fail) seems like a
>> reasonable command to issue... isn't that out of the book?
>>
>> Inspecting minikanren.ss reveals that, indeed, it doesn't export any
>> "fail."  The mk.scm on Sourceforge includes the following two definitions
>>
>> (define succeed (lambdag@ (s) (unit s)))
>> (define fail (lambdag@ (s) (mzero)))
>>
>> which you can't issue yourself, because the version on PLaneT exports
>> neither lambdag@ nor mzero.  Try instead
>>
>> #lang scheme
>> (require (planet dfriedman/miniKanren:1:1/minikanren))
>> (define succeed (== #t #t))
>> (define fail (== #t #f))
>> (run #f (q) fail)
>>
>> That seems to fail correctly.  I don't have my copy of TRS at hand, so I
>> can't opine further.
>>
>> Hope that helps,
>> Ben
>>
>>
>
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