Re: In future, to replace autotools by cmake like KDE4 did?

From: J.C. Pizarro <jcpiza@gmail.com>
Date: Dec 7, 2007, 14:42 UTC
Message-ID: <998d0e4a0712070642u6ae75232t9cb5bfd0920b2439@mail.gmail.com>
In-Reply-To: <200712071456.11019.jnareb@gmail.com>

On 2007/12/7, Jakub Narebski <jnareb@gmail.com> wrote:

Show 32 quoted lines

> Andreas Ericsson wrote:
> > Jakub Narebski wrote:
> > >
> > > Although there was some talk about whether giw should use autotools,
> > > or perhaps CMake, or handmade ./configure script like MPlayer IIRC,
> > > instead of its own handmade Makefile...
> > >
> >
> > To tell the truth, I'd be much happier if everything like that got
> > put in a header file or some such. 95% of what we figure out by looking
> > at "uname" output can already be learned by looking at the various
> > pre-defined macros.
> >
> > Fortunately, there's a project devoted solely to this, so most of
> > the tedious research need not be done. It can be found at
> > http://predef.sourceforge.net/
>
> Code talks, bullsh*t walks.
>
> Pre-defined macros cannot tell us if one have specific libraries
> installed, cannot tell us if formatted IO functions support 'size
> specifiers' even though compiler claim C99 compliance or even though
> compiler doesn't claim C99 compliance but supports this, etc.
>
> But perhaps the "uname" based compile configuration could be replaced
> by testing pre-defined macros... at least for C code, and git is not
> only C code.
>
> --
> Jakub Narebski
> Poland
>

A powerful tool can do better things that old generators-based tools (as autotools).

To imagine, there are many scripts in subdirectories or subprojects:

* Before: (many copy and paste of code as below paragraph)
A_VARIABLE_OS = `uname -a | grep .... `  # <- slow
case "$A_VARIABLE_OS" in
   *linux*) ... ;;
   *bsd*) ... ;;
   *aix*) ... ;;
   *) ...;;
esac
m4 foo.sh.m4 > bar.sh # <- very slow
./bar.sh

* Later: (with the powerful tool that had cached many predefined variables in
                   a ramdisk's file or in a daemon's memory)
# call once at 1st time to internal uname of powerful tool for all ocurrences of
# below predefined variable from many scripts:
case "$FOO_VARIABLE_OS" in
   *linux*) ... ;;
   *bsd*) ... ;;
   *aix*) ... ;;
   *) ...;;
esac
# i don't need to generate more scripts to inspect still more it.

   J.C.Pizarro