Re: [PATCH] Extensions for SRFI-171 (Transducers)

[Damien Mattei <damien.mattei@gmail.com>]

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i just understood the scheme :-)

scheme@(guile-user)> (list-transduce (compose (tfilter (λ (x) x))
(tdelete-duplicates)) rcons (list 1 2 #f 3 3 4))
$12 = (1 2 3 4)

sorry...


On Thu, Dec 22, 2022 at 3:33 PM Damien Mattei <damien.mattei@gmail.com>
wrote:

> hello,
> just trying transducers before using it, i try to understand.
> what is wrong with that:
> scheme@(guile-user)> (list-transduce (tfilter (λ (x) x))
> (tdelete-duplicates) (list 1 2 #f 3 3 4))
> ice-9/boot-9.scm:1685:16: In procedure raise-exception:
> Wrong number of arguments to #<procedure 10786aa60 at
> srfi/srfi-171.scm:338:2 (reducer)>
>
> Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
>
> Regards,
> Damien
>
> On Wed, Dec 21, 2022 at 11:01 AM Linus Björnstam <
> linus.bjornstam@veryfast.biz> wrote:
>
>> As the author of both the SRFI and the guile code I am very happy you
>> like it. I don't have a computer at the moment, but I looked through the
>> code and it looked great.
>>
>> All additions should have been included in the original SRFI :)
>>
>> one comment: your code uses define-public, which the rest of SRFI-171
>> code does not.
>>
>> I am not in any position to sign code off for inclusion in guile proper,
>> but if the define-public thing is fixed it very much has my blessing.
>>
>> Best regards
>>   Linus Björnstam
>>
>> On Wed, 21 Dec 2022, at 01:48, Colin Woodbury wrote:
>> > Happy holidays everyone, I hope everything is going well for you.
>> >
>> > Since discovering SRFI-171 (Transducers) I have fallen in love with it.
>> > Transducers let me "talk the way I want to talk" while knowing that I'm
>> > being efficient underneath w.r.t. to iteration and allocation. In using
>> > Guile's implementation, I noticed a few common idioms missing that are
>> > otherwise present in other languages, so I've added them in a series of
>> > patches. I've been using these often for a number of weeks without
>> > issue, but of course have added unit tests as well.
>> >
>> > The full details are in the commit messages, but here are the main
>> highlights:
>> >
>> >  * rfold: The fundamental reducer. This allows the user to turn any
>> > two-arg function into a valid reducer, so that they don't need to worry
>> > about hand-writing reducers via case-lambda.
>> >  * rfind: Yields the first item in the transduction that matches some
>> > predicate. Nice for locating some specific value from a potentially
>> > large data source (e.g. a port).
>> >  * twindow: Like tsegment, but yields overlapping slices into the data.
>> > Cheers, and have a great holiday.
>> >
>> > Colin
>> >
>> > Attachments:
>> > * 0001-srfi-171-add-twindow-and-various-reducers.patch
>> > * 0002-doc-add-new-SRFI-171-reducers-to-the-manual.patch
>> > * 0003-srfi-171-add-unit-tests-for-new-functions.patch
>>
>>

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