Re: CGI::Application and object inheritance

When you assign to @ISA, you are removing the reference to CGI::Application. Putting a print "@ISA\n" after the use base... line and then after the @ISA=... line shows the problem:

package Foo;
                                                                      
+          
use base 'CGI::Application';
print "@ISA\n";
use Bar;
@ISA = ("Bar");
print "@ISA\n";

# at this point Foo only inherits from Bar

__END__
CGI::Application
Bar
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Rather than mixing use of use base and directly assigning to @ISA, consider the use of @ISA alone:

use CGI::Application;
use Bar;
@Foo::ISA = qw(CGI::Application Bar);
[download]

BTW, I believe "bar" should be capitalized in your original code.

--sacked

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Re^2: CGI::Application and object inheritance by ikegami (Patriarch) on Jul 27, 2005 at 14:58 UTC
The order of your statements is deceptive. `use` happens at compile time, so your code actually runs them in the following order: `package Foo; use base 'CGI::Application'; use Bar; print "@ISA\n"; @ISA = ("Bar"); print "@ISA\n";` [download] The first `print` should be wrapped in a begin to have it exected at before the `use Bar`. Same results in this case, but it's something for which one should look out, especially when demonstrating a point.	[reply] [d/l] [select]

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Re^2: CGI::Application and object inheritance
by ikegami (Patriarch) on Jul 27, 2005 at 14:58 UTC

The order of your statements is deceptive. use happens at compile time, so your code actually runs them in the following order:

package Foo;

use base 'CGI::Application';
use Bar;

print "@ISA\n";
@ISA = ("Bar");
print "@ISA\n";
[download]

The first print should be wrapped in a begin to have it exected at before the use Bar.

Same results in this case, but it's something for which one should look out, especially when demonstrating a point.

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