[racket] Are there Racket structures similar to Common Lisp's?

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Fri Aug 17 08:35:03 EDT 2012

It does not exit at the moment, but it should be macro definable. 
If you do develop a defstruct library, let me suggest you use 
Racket keywords for field tags: 

  (person #:age 35 #:favorite-color "blue" #:name "Bob")

As for NIL as default value, I question this idea very much. 
But then, Racket isn't Common Lisp and Common Lisp isn't Racket. 


On Aug 17, 2012, at 4:20 AM, Rouben Rostamian wrote:

> No, not really.  I am looking for structures a la Common Lisp,
> as described in the example that I gave.  The essential feature
> there is that the constructor may receive the structure's fields
> in any order.  There is no ambiguity because each field value
> is associated with field tag.
> I think I should be able to come up with a reverse-engineered
> version of that in Racket but I don't want to reinvent the wheel
> if it already exists.
> -- rr
> On Thu, Aug 16, 2012 at 10:44:08PM -0600, Richard Cleis wrote:
>> Are you asking for stuff like this?
>> http://docs.racket-lang.org/reference/define-struct.html
>> On Aug 16, 2012, at 10:09 PM, Rouben Rostamian wrote:
>>> Is there the equivalent of Common Lisp's /structure/ type in
>>> Racket?  I looked through Racket's User Guide and Reference
>>> manuals but did not see something similar, although it's
>>> quite possible that I saw one but did not recognize it.
>>> Specifically, here is what I want.  Consider the Common Lips
>>> definition of a /person/ structure:
>>> (defstruct person
>>>          name
>>>          age
>>>          waist-size
>>>          favorite-color)
>>> Then create an instance:
>>> (make-person :age 35
>>>            :favorite-color "blue"
>>>            :name "Bob")
>>> The latter echos:
>>> Let's note that the order of fields when invoking /make-person/
>>> need not be the same as the order in which the /person/
>>> structure is defined.
>>> Furthermore, since /waist-size/ was not specified at invocation,
>>> it was assigned NIL.
>>> -- 
>>> Rouben Rostamian
>>> ____________________
>>> Racket Users list:
>>> http://lists.racket-lang.org/users
> ____________________
>  Racket Users list:
>  http://lists.racket-lang.org/users

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 4373 bytes
Desc: not available
URL: <http://lists.racket-lang.org/users/archive/attachments/20120817/ad633dd1/attachment-0001.p7s>

Posted on the users mailing list.