fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (11 Jun 2021 18:15 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (11 Jun 2021 20:15 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (11 Jun 2021 22:27 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (12 Jun 2021 16:44 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (12 Jun 2021 19:58 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (12 Jun 2021 19:15 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (12 Jun 2021 20:07 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (12 Jun 2021 22:18 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (12 Jun 2021 22:20 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (13 Jun 2021 08:36 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (13 Jun 2021 19:19 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (13 Jun 2021 19:39 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (14 Jun 2021 00:18 UTC)
(missing)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (14 Jun 2021 14:53 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (14 Jun 2021 14:59 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (14 Jun 2021 15:15 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (14 Jun 2021 15:42 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (14 Jun 2021 15:44 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (14 Jun 2021 15:41 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (14 Jun 2021 16:10 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (14 Jun 2021 16:28 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (14 Jun 2021 17:12 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (14 Jun 2021 18:27 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (14 Jun 2021 18:43 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (14 Jun 2021 05:50 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (14 Jun 2021 07:40 UTC)
Re: fxmapping-unfold(-maybe) John Cowan (12 Jun 2021 23:54 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (13 Jun 2021 14:13 UTC)
Re: fxmapping-unfold(-maybe) Shiro Kawai (15 Jun 2021 04:18 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (15 Jun 2021 06:16 UTC)
Re: fxmapping-unfold(-maybe) Shiro Kawai (15 Jun 2021 09:44 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (15 Jun 2021 10:37 UTC)
Re: fxmapping-unfold(-maybe) Shiro Kawai (15 Jun 2021 14:20 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (15 Jun 2021 14:33 UTC)
Re: fxmapping-unfold(-maybe) John Cowan (15 Jun 2021 23:08 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (16 Jun 2021 06:48 UTC)
Re: fxmapping-unfold(-maybe) John Cowan (18 Jun 2021 03:01 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (18 Jun 2021 06:26 UTC)
Re: fxmapping-unfold(-maybe) Ray Dillinger (20 Jun 2021 04:08 UTC)
Re: fxmapping-unfold(-maybe) Shiro Kawai (20 Jun 2021 04:28 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (20 Jun 2021 08:00 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (20 Jun 2021 16:17 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (20 Jun 2021 16:19 UTC)
Re: fxmapping-unfold(-maybe) Arthur A. Gleckler (20 Jun 2021 16:25 UTC)
Re: fxmapping-unfold(-maybe) Shiro Kawai (17 Jun 2021 17:32 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (17 Jun 2021 18:00 UTC)
Re: fxmapping-unfold(-maybe) Shiro Kawai (17 Jun 2021 21:25 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (18 Jun 2021 06:09 UTC)
Re: fxmapping-unfold(-maybe) Shiro Kawai (19 Jun 2021 22:05 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (20 Jun 2021 07:00 UTC)
Re: fxmapping-unfold(-maybe) Shiro Kawai (20 Jun 2021 07:36 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (20 Jun 2021 08:31 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (20 Jun 2021 09:10 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (20 Jun 2021 10:44 UTC)
Re: fxmapping-unfold(-maybe) Shiro Kawai (20 Jun 2021 21:39 UTC)
Re: fxmapping-unfold(-maybe) Marc Nieper-Wißkirchen (21 Jun 2021 06:09 UTC)
Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe (17 Jun 2021 18:01 UTC)
Re: fxmapping-unfold(-maybe) John Cowan (12 Jun 2021 04:06 UTC)

Re: fxmapping-unfold(-maybe) Wolfgang Corcoran-Mathe 11 Jun 2021 20:15 UTC

On 2021-06-11 20:02 +0200, Marc Nieper-Wißkirchen wrote:
> fxmapping-unfold and fxmapping-unfold-maybe should probably take an
> arbitrary number of seeds to allow multiple values piped through.

That makes sense to me, and it's not a big change.

> In any case, your example shows that the old unfold protocol (stemming from
> SRFI 1 and present in many SRFIs) should be revised. It's obviously not a
> good abstraction.

You mean the "three procedure" unfold,
(X-unfold stop? mapper successor seed)?  Possibly so.  I think there
are cases in which the separate procedures are useful, but the
equivalent Maybe/CPS version is often more efficient, as the SRFI
notes.

> PPS There's one more argument why the Maybe abstraction is a flawed one:
> With Maybe you can only simulate two callbacks. That suffers for the
> callback procedures in SRFI 224, but it won't in general. For consistency,
> one should focus on a protocol that is generalizable.

I don't fully understand.  Is the argument that a binary sum type
isn't good because sometimes we want a ternary sum type, and so on?
I think it's clear that the "failure/success" paradigm shows up so
often as to be a useful pattern to capture, in its own right.

--
Wolfgang Corcoran-Mathe  <xxxxxx@sigwinch.xyz>

"This isn't right. This isn't even wrong." --Wolfgang Pauli