Angel has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks

I was wondering can I call an object inside another object? I get an error of the method is to be called from main instead of the object. 
package bar;

use foo;

sub new
{
    my($type) = $_[0];
    
    my($self) = {};
    
    $self->{'new'} = 1;
    
    #error reporting and update vars
    $self->{error_type}    = undef;
    $self->{error_string}  = undef;
  
    bless($self, $type);
    

    
    return( $self );

}


sub generate_form()
{
    my $self  = shift;
    
    my $foo = Foo->new;
    
    print $foo->do_something( "bunny" );
    
}

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Re: Objects in Objects
by bobn (Chaplain) on Aug 23, 2003 at 02:59 UTC

    Not this way. You say use foo, then you call Foo->new - case matters.

    It looks sort of like you're trying to do inheritance, which is usually done more like: 

    
#!/usr/bin/perl -w

package foo;

sub new
{
   my ($class, @stuff) = @_;
   my $self = {};
   # do stuf with $self and @stuff...
   bless {}, $class;
}

sub do_something
{
   my ($self, @parms) = @_;
   print "in do_something: $self, @parms\n";
}

package bar;

# if foo is in another file, also say "use foo;" here
@ISA = qw/foo/;
# "use base qw( foo );" can be used in place of the preceding 2 lines 
+in perl >= 5.004_04 (I think), certainly by 5.6.0.


sub do_something_else
{
   my ($self, @parms) = @_;
   print "in do_something_else, $self, @parms\n";
}

package main;

my $b = new bar;
$b->do_something('stuff');
$b->do_something_else('stuff2');

__END__

    [download]
    Results in: 
    in do_something: bar=HASH(0x804ca30), stuff
in do_something_else, bar=HASH(0x804ca30), stuff2

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    new and do_something, not defined in bar, still work because they are inherited from foo. do_something_else is defined in bar. so it works too.

    All code given here is UNTESTED unless otherwise stated.

    --Bob Niederman, http://bob-n.com
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Re: Objects in Objects
by Anonymous Monk on Aug 23, 2003 at 10:59 UTC
    Executing the code 
    #!perl

use strict;
use warnings;

package Foo;

sub new
{
   my $class = shift;
   bless [], $class;
}

sub doFoo
{
   my $obj = shift;
   print "foo::doFoo => @_\n";
}

package Bar;

sub new
{
   my $class = shift;
   bless [], $class;
}

sub doBar
{
   my $obj = shift;
   my $nfoo = new Foo;
   $nfoo->doFoo(@_);
   print "Bar::doBar => @_\n";
}

package main;

my $b = new Bar;
$b->doBar(qw(i feel lucky));

    [download]
    I don't get your error. Do you really have the two lines 
    use foo;
...
    my $foo = Foo->new;

    [download]
    If so, just fix the case. If not, please post a small piece of code that reproduces the error you are getting (in this case probably two small modules and one small program).
    Oh, and remember: use strict; use warnings;.
    Cheers, CombatSquirrel.
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      Don't forget to login before you post CombatSquirrel. :)

      This is why i tell everyone here to change their theme. GOTO your User Settings and scroll on down to 'Theme Configuration'. Change your theme to anything but the default theme. Now, when you bring up Perlmonks in your browser, if you see the default theme - you know you are not logged in. Also, while you are at your User Settings, feel free to add some custom CSS - i have added background images to mine. Know i really know if i am logged in or not!

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      jeffa

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(the triplet paradiddle with high-hat)
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        Yeah, sorry, jeffa. I'm fiddling around with the CSS at the moment; the only problem is that I like the standard theme too much - I hate those overloaded web pages, or me, beauty lies in simplicity. I'll try to make the CSS affect only an unimportant portion of the page that I'll nevertheless notice. I just tried font[size="2"] { color:blue }, but that made all the replies colored blue - quite ugly.
        Well, thanks for your reminder anyways.
        CombatSquirrel.
        P.S.: Changed it to form { color:blue } - still sub-optimal, but a lot better.
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