Re: Find an element in a functional set (guile-pfds)

On 07.07.24 13:01, Maxime Devos wrote:
>
> >Maybe bbtree-fold can be used, but
>
> that would not "early exit" as soon as it has found an item, that satisfies some
>
> specified predicate.
>
> You can use escape continuations to do an early exit:
>
> ;; On success, return stuff-to-return. Otherwise, return the symbol ‘no-match’.
>
> (let/ec escape
>
>   (bbtree-fold [...] [... when a match is found, use (escape stuff-to-return)] 
> [...])
>
>   'no-match)
>
> Best regards,
>
> Maxime Devos.
>
Ah what wonderful idea! I did not think of it! Thank you!

There is one more issue though: The underlying tree implementation cannot be 
accessed from the functions exported by the set module. I guess I could get at 
that using some @@ magical thing?

In the end it would still feel a bit like a hack to hack around the limited 
exports of the module, but I guess I would have exported that function anyway, 
had I to write this implementation, so I figure that would be OK.

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