Date: Fri, 5 Dec 2008 16:05:21 +0300 From: Eygene Ryabinkin <rea-fbsd@codelabs.ru> To: Garrett Cooper <yanefbsd@gmail.com> Cc: Maksim Yevmenkin <maksim.yevmenkin@gmail.com>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: RFC: small syscons and kbd patch Message-ID: <WUFHrI95zEo9/wlGGrRYnWztEtI@qm7gbYKMPO53E/nl%2BD5eD8YyL1A> In-Reply-To: <7d6fde3d0812050050l57684eebkf14f252d78b68ec0@mail.gmail.com> 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> <7d6fde3d0812050050l57684eebkf14f252d78b68ec0@mail.gmail.com>
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--/e2eDi0V/xtL+Mc8 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Garret, Fri, Dec 05, 2008 at 12:50:38AM -0800, Garrett Cooper wrote: > 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)? It is the standard negation operator: !(expr) is equal to (expr =3D=3D 0). > 2. Is it still taught in schools (I didn't learn it when I was taught > C)? Yes. I am personally teaching the people in school and I am explaining the concept of double negation every two years ;)) > If not in schools, what about the Richie text (it's sort of like > the defacto C programming standard book of course)? K&R book is good but it at no means covers all tricks and idioms of a C language. > 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? No real loss, just easier to type and looks more compact. It is the matter of a personal taste, I think. If one knows this idiom, he will recognize it at a glance. If not, one should think a bit about the logics behind it, but it shouldn't be hard: almost everyone uses constructs like 'if (!ptr)'. And there is only one step from there to the double negation. --=20 Eygene _ ___ _.--. # \`.|\..----...-'` `-._.-'_.-'` # Remember that it is hard / ' ` , __.--' # to read the on-line manual =20 )/' _/ \ `-_, / # while single-stepping the kernel. `-'" `"\_ ,_.-;_.-\_ ', fsc/as # _.-'_./ {_.' ; / # -- FreeBSD Developers handbook=20 {_.-``-' {_/ # --/e2eDi0V/xtL+Mc8 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) iEYEARECAAYFAkk5JxEACgkQthUKNsbL7YguFACgitCINYMboc3XROsVpHiqZXJS lGoAn1wsMu62iIqyfyBJ1GbtFln1sISV =mxfg -----END PGP SIGNATURE----- --/e2eDi0V/xtL+Mc8--
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