[plt-scheme] Structure constructor

From: Jens Axel Søgaard (jensaxel at soegaard.net)
Date: Mon Jul 17 14:26:58 EDT 2006

Robby Findler wrote:

>At Mon, 17 Jul 2006 14:16:00 -0400, Sam TH wrote:
>  
>
>>On Mon, 2006-07-17 at 20:03 +0200, Jens Axel Søgaard wrote:
>>    
>>
>>>Hi all,
>>>
>>>What is the simplest way to go from a structure to its constructor?
>>>The following seems to work, but I have a hunch there is a simpler
>>>solution.
>>>      
>>>
>>I think you want `struct-type-make-constructor'.  Then your function can
>>be defined as:
>>
>>(define (struct-constructor s)
>>  (define-values (sty _) (struct-info s))
>>  (struct-type-make-constructor sty))
>>    
>>
>
>You can also get that information at elaboration time, if you have the
>"s" in (define-struct s (a b)) around. define-struct's docs should
>explain how to extract it, I believe.
>  
>
Yes, in this case I need it at evaluation time though. I am writing a 
general clone
function for syntax trees represented by structures.

-- 
Jens Axel Søgaard




Posted on the users mailing list.