[pro] BOA constructor and supplied-p argument

[Pascal Costanza]

I think this is a bug in SBCL, and should be reported with its maintainers.

Pascal

On 10 Jun 2011, at 16:53, Tamas K Papp wrote:

> Hi,
> 
> I tried to save a supplied-p parameter from a BOA constructor like this:
> 
> (defstruct (delayed-iseq
>             (:constructor iseq (start-or-end 
>                                 &optional (end 0 end?) (by 1)
>                                 strict-direction?)))
>  "Delayed index sequence evaluation."
>  start-or-end end end? by strict-direction?)
> 
> but SBCL complained that end? was not used.  After rereading the CLHS
> page for defstruct, I am still not 100% sure why this is.  My
> intepretation is that END? is an argument like any other, but probably I
> am not getting something.
> 
> Anyhow, instead I used
> 
> (defstruct delayed-iseq
>  "Delayed index sequence evaluation."
>  start-or-end end end? by strict-direction?)
> 
> (defun iseq (start-or-end &optional (end 0 end?) (by 1) strict-direction?)
>  (make-delayed-iseq :start-or-end start-or-end :end end :end? end? :by by
>                     :strict-direction? strict-direction?))
> 
> Is there a way to do it in a single defstruct definition?
> 
> Best,
> 
> Tamas
> 
> PS.: (eq end nil) is different from when it is not supplied, hence the
> need to save end?.
> 
> 
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--
Pascal Costanza