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Date:      Tue, 20 Mar 2012 21:40:39 +0000
From:      Chris Rees <utisoft@gmail.com>
To:        John Baldwin <jhb@freebsd.org>
Cc:        svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org
Subject:   Re: svn commit: r233052 - head/share/mk
Message-ID:  <CADLo839N=N_yqQy1opR1b5%2B5S0O5a-sdxV-PG9DEGfESPTDhMA@mail.gmail.com>
In-Reply-To: <201203201728.21049.jhb@freebsd.org>
References:  <201203162319.q2GNJjx5039482@svn.freebsd.org> <201203201019.40486.jhb@freebsd.org> <CADLo839Ef3bu_14AdexOWapOacFLk3MM9HK-oNLmtA52Cc9C6w@mail.gmail.com> <201203201728.21049.jhb@freebsd.org>

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On 20 March 2012 21:28, John Baldwin <jhb@freebsd.org> wrote:
> On Tuesday, March 20, 2012 5:20:04 pm Chris Rees wrote:
>> On 20 March 2012 14:19, John Baldwin <jhb@freebsd.org> wrote:
>> > On Monday, March 19, 2012 5:39:53 pm Doug Barton wrote:
>> >> On 3/19/2012 12:37 PM, Dimitry Andric wrote:
>> >> > It would be much nicer to be able to write:
>> >> >
>> >> > .if defined(FOO)
>> >> > =A0 .if defined(BAR)
>> >> > =A0 =A0 CFLAGS+=3D =A0 =A0 =A0 =A0-DFOO_BAR
>> >> > =A0 .endif
>> >> > .endif
>> >>
>> >> Take a look at /usr/ports/Mk/bsd.port.mk for how this can be done.
>> >
>> > Hmm, do yoo have a specific example? =A0The bits in I see in bsd.port.=
mk
> suffer
>> > from the limitation Dimitry raises, e.g.:
>> >
>> > .if defined(OPTIONS)
>> > # include OPTIONSFILE first if exists
>> > . =A0 =A0 =A0 if exists(${OPTIONSFILE}) && !make(rmconfig)
>> > . =A0 =A0 =A0 include "${OPTIONSFILE}"
>> > . =A0 =A0 =A0 endif
>> > . =A0 =A0 =A0 if exists(${OPTIONSFILE}.local)
>> > . =A0 =A0 =A0 include "${OPTIONSFILE}.local"
>> > . =A0 =A0 =A0 endif
>> > WITHOUT:=3D
>> > WITH:=3D
>> > . =A0 =A0 =A0 if defined(OPTIONS)
>> > REALOPTIONS=3D${OPTIONS:C/".*"//g}
>> > . =A0 =A0 =A0 for O in ${REALOPTIONS}
>> > RO:=3D${O}
>> > . =A0 =A0 =A0 if ${RO:L} =3D=3D off
>> > WITHOUT:=3D =A0 =A0 =A0 ${WITHOUT} ${OPT}
>> > . =A0 =A0 =A0 endif
>> > . =A0 =A0 =A0 if ${RO:L} =3D=3D on
>> > WITH:=3D =A0 =A0 =A0 =A0 =A0${WITH} ${OPT}
>> > . =A0 =A0 =A0 endif
>> > OPT:=3D${RO}
>> > . =A0 =A0 =A0 endfor
>> > . =A0 =A0 =A0 endif
>> >
>> > That is, all the lines that don't start with a . are not indented, and
>> > even this indentation is rather horrible (it doesn't nest, and it
>> > has the odd structure of 'if defined(OPTIONS) { if defined(OPTIONS) {}=
 }'.
>>
>> I don't see how it's any more horrible than the kernel style's rules
>> on indented #ifs (though I can see the reasoning for that)
>>
>> It's an unfortunate consequence of the fact that any line starting
>> with whitespace must be a shell command-- from before Makefiles were
>> allowed conditionals etc.
>>
>> It's got to be an improvement on:
>>
>> .if defined(ONE)
>> .if !defined(TWO)
>> .for one in two three four
>> .if ${VAR} =3D=3D ${one}
>> .if defined(VERBOSE)
>> .warning VAR =3D one
>> .endif
>> .endif
>> .endfor
>> .elif ${VAR} =3D=3D four
>> .if defined(VERBOSE)
>> .warning VAR =3D four
>> .endif
>> .else
>> .warning VAR is not four, and VERBOSE is ignored
>> .endif =A0 =A0# XXXX Which one is this for??
>> .endif
>>
>> which is what a lot of the Makefiles look like... debugging if-less
>> endifs etc is infinitely easier if we indent, however horrible it
>> looks.
>>
>> We shouldn't be *trying* to make Makefiles hard to read ;)
>
> Oh, it may be that I was reading it in less or some such and that bsd.por=
t.mk
> requires 4 space tabs, so when viewed in things like less the indentation
> doesn't actually look like indentation. =A0In that respect, this is no be=
tter
> than the above (and is what bsd.ports.mk looks like to me at least):
>
> . =A0 =A0 =A0if defined(ONE)
> . =A0 =A0 =A0if !defined(TWO)
> . =A0 =A0 =A0for one in two three four
>
> etc. =A0To be worthwhile the spacing has to actually look like indentatio=
n:
>
> .if defined(ONE)
> . =A0if !defined(TWO)
> . =A0 =A0for one in two three four
>
> etc.

Yes-- it'd be nice if less could read the ex:ts=3D4 bit.

That can go on my todo list.

Chris



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