From: ludo@gnu.org (Ludovic Courtès)
To: Andreas Rottmann <a.rottmann@gmx.at>
Cc: guile-devel@gnu.org
Subject: Re: binary-port?
Date: Mon, 25 Apr 2011 16:08:44 +0200 [thread overview]
Message-ID: <8739l6mnir.fsf@gnu.org> (raw)
In-Reply-To: <87hb9mwnnd.fsf@gmx.at> (Andreas Rottmann's message of "Mon, 25 Apr 2011 13:55:50 +0200")
Hi,
Andreas Rottmann <a.rottmann@gmx.at> writes:
> ludo@gnu.org (Ludovic Courtès) writes:
>>>> However, I’m wondering whether we should not just squarely do away with
>>>> the binary/textual distinction, and just write:
>>>>
>>>> (define (binary-port? p) #t)
>>>>
>>>> What do people with experience with pure R6RS code think? Is the
>>>> distinction actually used, and how?
>>>>
>>> I can only find one example in the code I wrote:
>>> `copy-port', which works (with the probably obvious semantics), on both
>>> binary and textual ports. On Guile, when `binary-port?' would return #t
>>> for all ports, `copy-port' would break, losing the transcoding effect
>>> you'd get when you pass two textual ports of different encodings.
>>
>> Interesting. Can you post a link to the code?
>>
> Sure, it's in `(spells ports)':
>
> https://github.com/rotty/spells/blob/master/spells/ports.sls
I see, thanks.
[...]
> So, my impression is that while `binary-port?' and `textual-port?' are
> not used widely, they do have their uses, and there is definitly code
> out there that relies on the binary/textual distinction.
OK.
> - Ikarus and Ypsilon definitly have disjoint ports.
>
> - Racket natively has ports that will accept both binary and textual
> operations, but it's R6RS support wraps these ports so that the
> resulting R6RS ports are not compatible with Racket's native port
> operations, but do provide the binary/textual disjointness.
So Racket really has 3 disjoint port types, right? That looks
inconvenient to me.
> These are the only implementations (besides Guile), that I'm familiar
> with. Ideally, Guile's R6RS support would provide real disjointness for
> binary and textual ports -- I think the only artefact that hampers this
> is that there's no way to distinguish Latin-1 encoded ports from "pure"
> binary ports (as both have `port-encoding' being #f).
And beyond that, you can put-bytevector on any port, read-char on any
port, and so on.
I wouldn’t want the “native” port type to be disjoint from the R6RS port
types, notably because there’s no “native” equivalent to the R6RS binary
I/O API, and also because it would hamper composition of R6RS and
non-R6RS code.
Thanks,
Ludo’.
next prev parent reply other threads:[~2011-04-25 14:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-22 22:28 binary-port? Ludovic Courtès
2011-04-23 1:48 ` binary-port? Andreas Rottmann
2011-04-23 19:56 ` binary-port? Ludovic Courtès
2011-04-24 6:39 ` binary-port? Marco Maggi
2011-04-24 13:03 ` binary-port? Ludovic Courtès
2011-04-25 11:55 ` binary-port? Andreas Rottmann
2011-04-25 14:08 ` Ludovic Courtès [this message]
2011-04-25 14:20 ` binary-port? Andy Wingo
2011-04-26 0:16 ` binary-port? Andreas Rottmann
2011-04-26 15:00 ` binary-port? Ludovic Courtès
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