[Cuis-dev] Methods that return multiple values

[Luciano Notarfrancesco]

Ah, great, I like this! Thanks!

On Wed, 21 Jun 2023 at 16:08 Juan Vuletich <juan at cuis.st> wrote:

> Hi Luciano,
>
> The style I learn from Squeak long time ago is to receive a block and
> evaluate it with the values that would be answered. In your example it
> would be
>
> a xgcd: b into: [ :g :s :t | ... ]
>
> It is very similar to what you propose, but it avoids creating an extra
> array. See, for example, senders of
> #barycentricCoordinatesInTriangle:with:with:into:ifDegenerate: and
> #nextUtf8BytesAndCodePointInto:into:
>
> This style doesn't require any additions to the image and is expressive
> enough in my opinion.
>
> Cheers,
>
> On 6/21/2023 10:13 AM, Luciano Notarfrancesco via Cuis-dev wrote:
> > Smalltalk doesn’t have a convention for methods returning multiple
> > values, and I’m not aware of any implementation.
> > An example of such thing is the extended gcd: ‘a xgcd: b’ returns g,
> > s, t where g is the gcd, and as + bt = g. Writing methods that return
> > multiple values is easy with the curly brackets syntax,
> > Integer>>#xgcd: ends with something like
> >     ^ {g. s. t}
> > But using sending messages that return multiple values is kind of
> > annoying, I end up doing something like:
> >     xgcd := a xgcd: b.
> >     g := xgcd at: 1.
> >     s := xgcd at: 2.
> >     t := xgcd at: 3
> > Some years ago I thought about using blocks for this, but I never
> > tried it. Today I just did a little experiment implementing anArray |
> > aBlock as ‘^ aBlock valueWithPossibleArgs: self’ and I can do:
> >     (a xgcd: b) | [:g :s :t| … ]
> >
> > This is seems quite nice already, I guess I’ll start using it and see
> > how it feels. But the point of this mail is not to show a solution,
> > but to ask if anyone have thought about this or if they know any nicer
> > solutions. Any ideas?
>
>
> --
> Juan Vuletich
> cuis.st
> github.com/jvuletich
> researchgate.net/profile/Juan-Vuletich
> independent.academia.edu/JuanVuletich
> patents.justia.com/inventor/juan-manuel-vuletich
> linkedin.com/in/juan-vuletich-75611b3
> twitter.com/JuanVuletich
>
>
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