in reply to simple tie?

Try something like : 
Package Tie::Hash::SaveConfig;

use strict;
use vars qw(@ISA);

@ISA = qw(Tie::StdHash);

sub TIEHASH {
 my $class = shift;
 my %hash;
 bless \%hash,$class;
}

sub STORE {
  my ($self,$key,$value) = @_;
  $self->SaveConfig($key,$value,$self->{$key});
  $self->{$key} = $value; #Redefine value
  return $value;
}

sub DELETE {
  my ($self,$key) = @_;
  $self->SaveConfig($key,$self->{$key});
  return $self->{$key};
}  

sub SaveConfig {
  my $self = shift @_;
  #Do something here
}

}

1;
__END__

[download]
Then tie it as follows... 
use Tie::Hash::SaveConfig;
my %hash = ();
tie %hash,'Tie::Hash::SaveConfig';
%hash = (Foo=>"Bar");

[download]
Check davorgs perl.com article

Greetz
Beatnik
... Quidquid perl dictum sit, altum viditur.

Replies are listed 'Best First'.
Re: Re: simple tie?
by Hofmator (Curate) on May 27, 2002 at 13:21 UTC

    Good answer, Beatnik! Allow me to suggest a simplification to your solution. Use SUPER;) and you don't need the TIEHASH routine.

    Package Tie::Hash::SaveConfig;
@ISA = qw(Tie::StdHash);

use strict;
sub STORE {
    my $self = shift;
    SaveConfig();
    $self->SUPER::STORE(@_);
    # or (probably better) here:
    # SaveConfig();
}
 
sub SaveConfig {
    # do something ...
    print "Config saved\n";
}

1;

    [download]

    Update: Note merlyn's comment below. I put an additional comment into the code. From the original post, though, it's not clear what is actually wanted.

    -- Hofmator

[reply]
[d/l]
          SaveConfig(); 
    $self->SUPER::STORE(@_);

      [download]
      I'd swap those two lines: that way the hash is in the new state before the config is saved, unless the point was to save the old config.

      -- Randal L. Schwartz, Perl hacker

[reply]
[d/l]
        Error: Variable "%userdata" is not imported at library.pl line 242. Here is the code:
        

sub some_sub {
    require 'wpconfig.cgi';
    tie(%config, 'tie::config');
    tie(%userdata, 'tie::config');
}

package tie::config;
@ISA = qw(Tie::StdHash);
use strict;

sub STORE {
    my $self = shift;
    $self->SUPER::STORE(@_);
    saveConfig();
}

# saveConfig: This is what actually saves wpconfig.cgi.
sub saveConfig {
    my $fh = main::open '>wpconfig.cgi';
    print $fh "# DO NOT MODIFY THIS FILE\n# IT IS GENERATED DYNAMICALL
+Y!!\n\n";
    print {$fh} main::genHash(config); # genHash just takes the hash a
+nd generated perl code for it.
    print {$fh} main::genHash(userdata); 
    print $fh "\n1;";
    close $fh;
}

package main;

# exit: Exits and unties %config and %userdata.
sub exit {
    untie(%config) if %config;
    untie(%userdata) if %userdata; # <- line 242
    CORE::exit();
}

        [download]
        This works fine (not errors) but it won't update the file.
        sub some_sub {
    require 'wpconfig.cgi';
    tie(%config, 'tie::config');
    tie(%userdata, 'tie::config');
}


package tie::config;

sub TIEHASH {}

sub STORE {
    my $self = shift;
    $self->SUPER::STORE(@_);
    saveConfig();
}

# saveConfig: This is what actually saves wpconfig.cgi.
sub saveConfig {
    my $fh = main::open '>wpconfig.cgi';
    print $fh "# DO NOT MODIFY THIS FILE\n# IT IS GENERATED DYNAMICALL
+Y!!\n\n";
    print {$fh} main::genHash(config);
    print {$fh} main::genHash(userdata);
    print $fh "\n1;";
    close $fh;
}

package main;

# exit: Exits and unties %config and %userdata.
sub exit {
    untie(%config) if %config;
    untie(%userdata) if %userdata;
    CORE::exit();
}

        [download]
[reply]
[d/l]
[select]
      Well I didn't really know what he wanted :) but a ++ ! :)

      Greetz
      Beatnik
      ... Quidquid perl dictum sit, altum viditur.
[reply]

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