[plt-scheme] Re: Simple procedure building question

Unless I am reading this backwards, don't use quote.


On Oct 20, 2008, at 5:05 PM, blockstack wrote:

> I figured it out. Thanks for the help.
> I needed to use list instead of quote.
>
> (define (B lst x y)
>   (if (null? lst)
>       '(y)
>       (cons (car lst) (cons x (list (B (cdr lst) x y))))))
>
> On Oct 20, 3:34 pm, "Andre Mayers" <andre.may... at usherbrooke.ca>
> wrote:
>> I was thinking that you want to end up with the list (f x (g x (m  
>> x (n x
>> y)))).
>> But if you want to eval the expression (f x (g x (m x (n x y))))  
>> you just do
>>
>> (define (B lst x y)
>>   (if (null? lst)
>>       y
>>       ((car lst) x (B (cdr lst) x y))))
>>
>> -----Message d'origine-----
>> De : plt-scheme-boun... at list.cs.brown.edu
>> [mailto:plt-scheme-boun... at list.cs.brown.edu] De la part de  
>> blockstack
>> Envoyé : October-20-08 4:20 PM
>> À : plt-sch... at list.cs.brown.edu
>> Objet : [plt-scheme] Re: Simple procedure building question
>>
>> doesn't the quote prevent the inner procedures in the else-expr from
>> being evaluated?
>>
>> On Oct 20, 3:02 pm, "Andre Mayers" <andre.may... at usherbrooke.ca>
>> wrote:
>>
>>> (define (B lst x y)
>>>   (if (null? lst)
>>>       y
>>>       `(,(car lst) ,x ,(B (cdr lst) x y))))
>>
>>> -----Message d'origine-----
>>> De : plt-scheme-boun... at list.cs.brown.edu
>>> [mailto:plt-scheme-boun... at list.cs.brown.edu] De la part de  
>>> blockstack
>>> Envoyé : October-20-08 3:56 PM
>>> À : plt-sch... at list.cs.brown.edu
>>> Objet : [plt-scheme] Re: Simple procedure building question
>>
>>> correction: i meant to have y for the then-expr
>>
>>> (define (B lst x y)
>>>     (if (null? lst)
>>>         y
>>>     ((car lst) x (B (cdr lst) x y))))
>>
>>> On Oct 20, 2:51 pm, blockstack <blockst... at gmail.com> wrote:
>>
>>>> I want to be able to pass a list of function names and create a
>>>> procedure
>>>> lst would be something like (f g m n) where f, g, m, and n are  
>>>> names
>>>> of functions
>>
>>>> (define (B lst x y)
>>>>    (if (null? lst)
>>>>        x
>>>>    ((car lst) x (B (cdr lst) x y))))
>>
>>>> I want to end up with a list like
>>>> (f x (g x (m x (n x y))))
>>
>>>> I know that my current procedure won't return a list, but I know  
>>>> that
>>>> it must be really simple to make it do so.
>>
>>>> I've tried different ways of using 'list' and cons, but I just  
>>>> can't
>>>> get it.
>>>> any help?
>>
>>>> _________________________________________________
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>>
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