From: "Linus Björnstam" <linus.internet@fastmail.se>
To: "Mark H Weaver" <mhw@netris.org>
Cc: guile-user@gnu.org
Subject: Re: Srfi-159/166 - monadic formatting for guile
Date: Fri, 14 Jun 2019 11:38:04 +0200 [thread overview]
Message-ID: <deebac0b-3f1d-4dd6-a5d3-4a2df87c2408@www.fastmail.com> (raw)
In-Reply-To: <87pnnj7pd9.fsf@netris.org>
Hi Mark!
I am not sure I understand what you mean, but i suspect it is already solved, since for simple cases show will use display/write. So unless you try to do advanced formatting of circular lists it will do whatever display or write does. The same thing goes for custom printers. In fact, anything that isn't a regular procedure will be printed just as it does in guile. Due to formatters being procedures, it is currently not possible to distinguish between formatters and other lambdas, but wrapping a lambda in (written ...) works just as (write ...).
So unless you tell show to do something else, it will default do guile's standard way.
(show #t (exact->inexact 1/7)) is the same as (display (exact->inexact 1/7)), however (show #t (with ((precision 2)) ...)) is not.
I don't know what circular structures guile uses internally, but (show...)ing a circular list without any formatter is, like numbers, the same as whatever guile does. (show #t (circular-list 1 2 3)) displays the same as (display (circular-list 1 2 3)).
Did I misunderstand your questions?
--
Linus Björnstam
On Wed, 12 Jun 2019, at 00:03, Mark H Weaver wrote:
> Hi Linus,
>
> Linus Björnstam <linus.internet@fastmail.se> writes:
>
> > I just ported the reference implementation of SRFI-159/166 (166 being
> > the successor of 159) from the reference implementation in chibi
> > scheme. The srfi document is here:
> > https://srfi.schemers.org/srfi-166/srfi-166.html
> >
> > SRFI-166 is like (ice-9 format) on steroids, drenched in molasses. It
> > can do a lot more than (ice-9 format), but about 3x slower. I haven't
> > started trying to make it fast just yet, but there are some low
> > hanging fruit (like speeding up simple cases). I will wait with
> > optimization until the srfi is finalized (and also maybe hear with
> > Alex what he has in mind before trying to half-ass it myself).
> >
> > Anyway, the repo is here: https://bitbucket.org/bjoli/guile-srfi-159
> > . I haven't ported the tests, but playing with it in guile and chibi
> > scheme produces the same result. Tests are up, but I'm travelling
> > without computer the next week, so there is no time.
>
> I would be in favor of integrating this into Guile at some point,
> although first I would like to make a careful review of the
> implementation to make sure that it integrates well with Guile's related
> mechanisms, e.g. custom record printers, printer options, and print
> states, and that it supports all Guile data types. In particular, I
> remember finding it difficult to properly implement cycle detection
> while supporting Guile's existing mechanisms. I'm not sure it can be
> done without modifying Guile's built-in printer.
>
> I'll also want to take a close look at the numeric formatter, to make
> sure that it achieves the same properties as our built-in printer,
> e.g. that it prints inexacts with the minimal number of digits required
> to ensure that the same number will be read back in (unless specifically
> asked to limit the precision).
>
> Anyway, thanks very much for sharing this!
>
> Regards,
> Mark
>
next prev parent reply other threads:[~2019-06-14 9:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-02 13:38 Srfi-159/166 - monadic formatting for guile Linus Björnstam
2019-06-02 20:31 ` Arne Babenhauserheide
2019-06-02 20:41 ` Ludovic Courtès
2019-06-03 5:34 ` Linus Björnstam
2019-06-03 13:07 ` Ludovic Courtès
2019-06-11 22:01 ` Mark H Weaver
2019-06-14 9:38 ` Linus Björnstam [this message]
2019-06-16 6:35 ` Mark H Weaver
2019-06-16 16:20 ` John Cowan
2019-06-16 19:30 ` Mark H Weaver
2019-06-18 10:39 ` Linus Björnstam
2019-06-16 20:30 ` Linus Björnstam
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