Re: Site Macro Directory

[Mark D. Roth]

On Fri May 24 12:35 2002 +0200, Akim Demaille wrote:
> | While working on this, I noticed that the current autom4te code
> | reverses the order of the `-I' options before passing them to m4.  The
> | documentation says:
> | 
> |   `--include=DIR'
> |   `-I DIR'
> |        Also look for input files in DIR.  Multiple invocations
> |        accumulate.  Contrary to M4 but in agreement with common sense,
> |        directories are browsed from last to first.
> | 
> | From my perspective, this behavior is extremely counter-intuitive.
> | Every other tool that I know of that accepts a `-I' option (including
> | gcc, GNU make, GNU m4, and perl) prepends the arguments to the search
> | path in the order specified.  As a result, I was extremely surprised
> | to discover that autoconf does the reverse.
> 
> Because the logic is to respect the last flag occurrence first for all
> the other flags but this one.  Honestly, to me it is a serious bug in
> all the other implementations.
> 
> And it *does* matter to autom4te, for instance because you do want
> sometimes to say ``I want _my_ macros to be used first''.  So you
> `autom4te -l autoconf -I .'.  But then, you want `.' to take precedence.

I completely agree that the directories specified in the `-I' options
should be checked before the others, but I don't think that requires
their order to be reversed.  Why doesn't autoconf simply read all the
`-I' options in order and prepend the complete list to the search
path?  That's what existing tools do; for an example, try this:

  perl -Ifoo -Ibar -Ibaz -e 'print join("\n", @INC) . "\n";'

It seems to me that this behavior would be much more intuitive and
wouldn't break anything.  What does everyone else think about this?


Anyway, I should have explicitly mentioned the `-I' directories in my
summary of the search path.  Here's what it should look like:

  1. Directories specified with the `-I' option.
  2. The current working directory ($top_srcdir).
  3. Directories specified in the $AC_MACRO_PATH environment variable
     (if set).
  4. The system-wide site macro directory (set when autoconf is
     installed).

Please let me know what you think.

-- 
Mark D. Roth <address@hidden>
http://www.feep.net/~roth/