Ciao Andrea

The presentation I attended gave me the idea of "ranting talks" at the next
ELS :)

Having said so, I now think that, to save goat and cabbage, what you want is

(defun foo (x y)
   (declare (*ftype* (function (integer number) number) *foo*))
   (+ x y))

Common lispers can live with that.

All the best

MA

On Tue, May 7, 2024 at 10:32 PM Andrea Corallo <acorallo@gnu.org> wrote:

> Marco Antoniotti <marco.antoniotti@unimib.it> writes:
>
> > Hi
> >
> > I am at ELS 2024 in Vienna and I saw Andrea Corallo's presentation about
> the introduction of the
> >
> > (defun foo (x)
> >     (declare (type (function (integer) float))
> >     (+ x 42.0))
> >
> > declaration.
> >
> > IMHO (and, I am not afraid to say, of many common lispers) this is
> shortsighted and a rather gratuitous departure from
> > what CL does.  With some potential unintended consequences down the road.
> >
> > The declaration proposed is for the signature of the function as a
> whole.  Using type may prevent ELisp from introducing
> > the usual CL idiom, as the following one
> >
> > (let ((x 42) (y -1))
> >     (declare (type integer x y)) ; The type declaration refers to names
> x and y.
> > ...)
> >
> > ... unless you special case the type declaration with no name(s)
> following the type spec.
> >
> > My suggestion: keep type (and ftype) for doing things the CL way (which
> was the PL/I way :) ) and introduce a signature
> > spec to be meaningful only at the function toplevel.
> >
> > (defun foo (x)
> >     (declare (signature (function (integer) float))
> >     (+ x 42.0))
> >
> > All the best
>
> Ciao Marco,
>
> I've no problem changing 'type' for something different if there's
> agreement, I don't especially like 'signature' as it's a bit verbose for
> my taste (but I could leave with it).
>
> Thanks
>
>  Andrea
>
> PS the presentation you attended must have been really terribile :)
>


-- 
Marco Antoniotti, Professor                   tel. +39 - 02 64 48 79 01
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