Date: Fri, 5 Dec 2008 00:50:38 -0800 From: "Garrett Cooper" <yanefbsd@gmail.com> To: "Erik Trulsson" <ertr1013@student.uu.se> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org>, Maksim Yevmenkin <maksim.yevmenkin@gmail.com> Subject: Re: RFC: small syscons and kbd patch Message-ID: <7d6fde3d0812050050l57684eebkf14f252d78b68ec0@mail.gmail.com> In-Reply-To: <20081205084441.GA29312@owl.midgard.homeip.net> References: <bb4a86c70812021701i621fdcfjb6a58a7f5cf781d5@mail.gmail.com> <7d6fde3d0812040324y3bf0901cy1f4a6d961362c314@mail.gmail.com> <bb4a86c70812040724w43ddec15yab72920d80d879d3@mail.gmail.com> <20081205072229.GE18652@hoeg.nl> <7d6fde3d0812050034y43a70ce8i49fbba92f9c8943b@mail.gmail.com> <7d6fde3d0812050035u6e3ea930o9e093830a8608444@mail.gmail.com> <20081205084441.GA29312@owl.midgard.homeip.net>
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On Fri, Dec 5, 2008 at 12:44 AM, Erik Trulsson <ertr1013@student.uu.se> wrote:
> On Fri, Dec 05, 2008 at 12:35:31AM -0800, Garrett Cooper wrote:
>> On Thu, Dec 4, 2008 at 11:22 PM, Ed Schouten <ed@80386.nl> wrote:
>> > * Maksim Yevmenkin <maksim.yevmenkin@gmail.com> wrote:
>> >> the idea was to ensure that kbd->kb_locked variable only takes values
>> >> 0 (zero) and 1 (one).
>> >
>> > I often use constructs like these to do that:
>> >
>> > foo = bar ? 1 : 0;
>> >
>> > Maybe !!bar is a lot shorter to write, I think the line above is a lot
>> > easier to read.
>>
>> Indeed. I had no idea (and I would assume that many people wouldn't in
>> my similar level of systems programming) what in the work you were
>> trying to do above with that line. The one-line conditional is
>> universal in almost all major high-level language dialects I've hit,
>> minus Python and Tcl.
>> -Garrett
>
> The !!bar construction to map {0, not-0} to {0,1} is fairly common in C
> programming, and I would certainly expect any experienced C programmer to
> recognize it.
(I feel like I'm getting off on a bikeshed topic, but...)
1. What dialect of C was it defined in? Is it still used in the
standard dialect (honestly, this is the first time I've ever seen it
before, but then again I am a younger generation user)?
2. Is it still taught in schools (I didn't learn it when I was taught
C)? If not in schools, what about the Richie text (it's sort of like
the defacto C programming standard book of course)?
3. What's the real loss of going to `? :', beyond maybe 3 extra
keystrokes if it's easier for folks who may not be as experienced to
read?
-Garrett
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