Date: Sun, 27 Apr 2008 15:38:54 -0500 From: Joshua Isom <jrisom@gmail.com> To: =?ISO-8859-1?Q?Romain_Tarti=E8re?= <romain@blogreen.org> Cc: hackers@freebsd.org, Romuald Conty <romuald.conty@free.fr> Subject: Re: indent(1) support for gcc(1) 0b prefix Message-ID: <d438888b768227b724504378c8f77b8e@gmail.com> In-Reply-To: <20080426213557.GA88577@marvin.blogreen.org> References: <20080426213557.GA88577@marvin.blogreen.org>
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On Apr 26, 2008, at 4:35 PM, Romain Tarti=E8re wrote: > Hello FreeBSD hackers! > > I'm using avr-gcc from the ports and relying on the 0b prefix notation > for binary constants, that is: > > foo =3D 0b00101010; > > Thanks to /usr/ports/devel/avr-gcc/files/patch-0b-constants this is > possible :-) > > But I would like to use indent(1) to reformat contributed code > automatically. Unfortunately, the 0b notation is not supported by that > program, and the resulting code looks like this: > > foo =3D 0 b00101010; > > ... then compilation fails, bla bla bla... > > A quick look at indent(1) source code leaded me to tweak > /usr/src/usr.bin/indent/lexi.c so that the 0b notation is supported > (patch attached). > > I was so wondering how useful(less) it was to support this extension = in > FreeBSD indent(1) program. The version of gcc provided with the base > system does not support this syntax, and AFAIK, only the avr-gcc port > support this kind of constructs... > > So options are: > - Add support for 0b notation to FreeBSD indent(1) (maybe requiring > the use of an extra command line argument to support this = feature); > - Provide a patch for indent(1) that can be conditionally applied on > the code when compiling the world; > - Create another port, say avr-indent(1), that is not more than a=20 > copy > of indent(1) with support of 0b constructs; > - Do nothing: tweaking indent(1) for supporting this is so trivial > that the few individuals interested in this can have their local > version of indent. > > Can you please tell me your opinion about this? > > Thank you in advance, > Romain > > PS: I also took a look at GNU indent (gindent(1) from the ports), but=20= > it > does not support 0b notation too. > > --=20 > Romain Tarti=E8re <romain@blogreen.org> =20 > http://romain.blogreen.org/ > pgp: 8DAB A124 0DA4 7024 F82A E748 D8E9 A33F FF56 FF43 (ID:=20 > 0xFF56FF43) > (plain text =3Dnon-HTML=3D PGP/GPG encrypted/signed e-mail much=20 > appreciated) > Why not just have a base2.h file that is a list of defines such as: #define b00000001 1 #define b00000010 2 Then you just use a b00 syntax, perfectly valid, and all's well=20 everywhere. Considering that the 0b syntax isn't valid without a patch=20= that's only available with one compiler that's probably not regularly=20 used, it'd probably be much more maintainable and not require anyone=20 compiling the program to install that specific port with that specific=20= patch. But of course, writing software that deals directly with bit fiddling=20 is annoying without using binary representation. The man page for indent does say "it has a 'forgiving' parser" so I=20 don't see why it can't just treat any token starting with a zero as=20 special, treat 0b01, 0x0A, 0f4 and 010 as a number regardless of the=20 base, even if it doesn't know the base.=
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