CLIM mail archive
Re: CLIM philosophy wrt to X.
Date: Mon, 26 Aug 91 11:28:57 -0400
Date: Mon, 26 Aug 91 09:45 EDT
From: "David C. P. Linden" <DCPL@fuji.ila.com>
Subject: CLIM philosophy wrt to X.
To: firstname.lastname@example.org, clim@BBN.COM
I don't think a macro would be a good idea because:
1. it would require low level routines to check if they should buffer or
not, and they are already slow enough.
The check cost could be as low the cost of a SLOT-VALUE operation.
Optimized implementations might manage to put this inline with the
output methods instead of defining :AFTER methods (which would introduce
2. if the macro was implemented as a closure, this would cons in those
Common LISP's that still don't stack allocate closures.
I think with-buffered-output is intended to be a sufficiently high level
macro that it is executed infrequently enough compared to the rest of
the program that consing a closure is relatively insignificant.
3. Usually i don't want lots of operations unbufferred, i just want to be
sure the buffer is flushed by a particular time.
and that's what force-output is for.
I think the original question was "What is CLIM's stance/convention on
getting output forced to the target, especially for interactive
streams?" X apparently requires programs to use a force-output
mechanism. Genera's DW doesn't. I know from hard experience that many
a Genera network program of mine didn't work initially because network
streams are buffered and I forgot to do a FORCE-OUTPUT. If I may
suggest some words into your (kanderson's) mouth, it sounds like you are
saying "I'd rather not get in the habit of depending on some streams
being auto-force-output, or even being tempted by having the option to
enable auto-force-output. I'm content with sprinking calls to
FORCE-OUTPUT in places I deem appropriate." Is that a fair statement?
It is reasonable and certainly safe across all HW&SW platforms that I
I'd rather just put FORCE-OUTPUT's where i know i really want the output
buffer emptied. I don't mind this being a noop on streams that don't
It would be reasonable for CLIM to put FORCE-OUTPUT's in some obvious
places like the loop inside TRACKING-POINTER, but i also think it is
reasonable to expect a developer to add others too.
General (beyond Lisp and CLIM) philosophy: There is one
auto-force-output scenario I think all bidirection streams should adher
to, and that is: "Doing a <read> operation with an empty read buffer
should do a FORCE-OUTPUT."
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