OK, I did it. Rather than my usual rant, lets post some bona-fide code. This is really rough, a lot of it is cut and paste from my other stuff, but at this point it's working. It may not work for you, as I've diked out a lot of the really ugly stuff before pressing submit ;-) Consider this untested.

package Config;

use strict;                           # always be strict
use Carp;
use vars qw ($AUTOLOAD);

my ($config);                        # our global config object

my (%config);                        # config hash, the actual config 
+data

sub new {

    my $proto = shift;
    my $class = ref($proto) || $proto;

    # setup the new object

    my $self = {
        %config,
           };
    
    bless ($self, $class);
    return ($self);
}

sub AUTOLOAD {
    my $self = $config;
    my $type = ref($self);
    my $name = $AUTOLOAD;

    $name =~ s/.*://;      # strip fully-qualified portion

    unless ( defined $self->{$name} ) {
      croak "Can't access `$name' field in class $type";
    }

    # just return the attribute
    return $self->{$name};
}

sub read_config {
  my $conf_file = shift;

  open (FILE, "$conf_file") || return 0;

  while (<FILE>) {
    if ( /^(\w+)\s*=?\s*(.*)$/ ) {
      $config->{$1} = $2;
      carp "w00t! set $1 to $2";
    }
  }

  close (FILE);

  return 1;
}

# package constructor

BEGIN {

  my (@config_files);

  $config = Config->new;

  # we have an empty configuration object, lets read in
  # a config file

  # if we fail, fail silently, give the user code a chance to call rea
+d_config
  # with it's own specifier

  @config_files = qw ( ../etc/journal.conf /usr/local/etc/journal.conf
+ );

  # try each one until we succeed
  foreach (@config_files) {
    if (read_config ($_)) {
      last;
    }
  }

  # error check
  if (! $config ) {
    carp "Failed to get config";
  }

}

# keep stuff happy

1;

[download]
With a config file like this:

rootdir = /usr/tmp

[download]
My code can do this:

use Config;

print "Root Directory is " . Config->rootdir . "\n";

[download]
All of my modules can use config;, the config data will only be read once.

The other bit of my criteria, allowing for a user override of the config file I haven't yet nutted out. I have a feeling it's going to cause me problems, given that some of my modules need config data during their class constructers. I'll keep on that.

In reply to Re: Program configuration in the OOP world by Tardis
in thread Program configuration in the OOP world by Tardis

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