Re: Problem with type conflict style warning

Hi

Vectors DO look like #(l am a vector) in Common Lisp and lists like (I am a
list).  What is the question?

MA



Marco Antoniotti
https://dcb.disco.unimib.it


On Thu, 16 May 2024 at 22:07, steve gonedes <[email protected]> wrote:

>
> On 5/15/24 8:11 AM, syll-dev wrote:
> > Hello
> >
> > I don't understand this style warning...
> >
> > Here is the code (problem with test1 only) :
> > "
> > (ql:quickload :alexandria)
> > (use-package :alexandria)
> >
> > (defvar *l* '(1 2 3))
> >
> > (defun test1 ()
> >    (copy-sequence 'vector (reverse *l*)))
> >
> > (defun test2 ()
> >    (copy-sequence 'vector *l*))
> >
> > (defun test3 ()
> >    (copy-sequence 'vector '(1 2 3)))
> >
> > (defun test4 ()
> >    (let ((l '(1 2 3)))
> >      (copy-sequence 'vector l)))
> > "
> >
> > And here is the result :
> > "
> > ; in: DEFUN TEST1
> > ;     (COPY-SEQUENCE 'VECTOR (REVERSE *L*))
> > ; --> BLOCK IF COERCE
> > ; ==>
> > ;   1
> > ;
> > ; caught STYLE-WARNING:
> > ;   Derived type of SB-C::X is
> > ;     (VALUES (OR LIST SB-KERNEL:EXTENDED-SEQUENCE) &OPTIONAL),
> > ;   conflicting with its asserted type
> > ;     VECTOR.
> > ;   See also:
> > ;     The SBCL Manual, Node "Handling of Types"
> > "
> >
> > sbcl 2.4.1 and 2.4.4 (other versions not tested).
> >
> > I have the same problem with remove-if-not instead of reverse.
> >
> > Thank you
> >
> > syll
> >
> >
> the function copy-sequence is in alexandria.
>
>
> (defun copy-sequence (type sequence)
>    "Returns a fresh sequence of TYPE, which has the same elements as
> SEQUENCE."
>    (if (typep sequence type)
>        (copy-seq sequence)
>        (coerce sequence type)))
>
>
> Here are some easy ones.
>
> ;;;; coerce
>
> (defparameter lst (list 1 2 3))
>
> (defun list-to-vector (lst)
>    (apply #'vector lst))
>
> (defun list-to-vector-coerce (lst)
>    (coerce lst 'vector))
>
> (list-to-vector-coerce lst)
> => #(1 2 3)
>
> (reverse #(1 2 3))
> (reverse (list 1 2 3 4))
>
>
> (remove-if-not #'oddp #(1 2 3 4 5))
> (remove-if #'evenp (list 1 2 3 4 5))
>
> => (1 3 5)
>
> I usually stay away from the external packages. it's a pain in the a$$ .
>
> The problem as I see it. vectors look like #(1 2 3 4) lists look like (1
> 2 3 4),
>
> notice the #
>
>
>
>
>
>
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>

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