[ale] OOP in perl

Christopher Fowler cfowler at outpostsentinel.com
Fri Apr 25 11:55:21 EDT 2003


You can not be 100% OOP in perl you can only be partial.  
Proof of that is being able to execute code outside of
classes.



On Fri, 2003-04-25 at 11:25, Jim Lynch wrote:
> All of the examples I've seen use hashes, I suspect it is a
> requirement.  At the risk of p*ssing off perl enthusiasts, IMHO, OOP
> perl is a bit of a hack.  The language wasn't designed to be OOP hence a
> hack.  Not to say it won't work and isn't efficient, but it "ain't"
> pretty.
> 
> You saw the my $ref = { ... } because that's a reference to a hash.  You
> used
> my %addr = which isn't a reference.  That's why you have to use the
> parens rather than the curly braces to delimit the content.  
> 
> Jim.
> 
> Christopher Fowler wrote:
> > 
> > Does all the data in an object *have* to be stored in a hash?
> > 
> > Could I just not have this:
> > 
> > my $name; my $line1; my $line2; my $city; my $state; my $zip;
> > 
> > This would be like I would do it in Java or C++.
> > 
> > Chris
> > 
> > On Fri, 2003-04-25 at 09:53, Jim Lynch wrote:
> > > Oh and it is common to have the last line of a perl module as:
> > >
> > > 1;
> > >
> > > Which does the same thing your return does.  That's described somewhere
> > > in the perl module documentation.
> > >
> > > Also, you aren't going to get quite what you expect.  This block
> > >
> > >     my %addr = { 'Name' => "",
> > >                  'Line1' => "",
> > >                  'Line2' => "",
> > >                  'City'  => "",
> > >                  'State' => "",
> > >                  'Zip'   => ""
> > >     };
> > >
> > > Should probably look like:
> > >
> > >     my %addr = ( 'Name' => "",
> > >                  'Line1' => "",
> > >                  'Line2' => "",
> > >                  'City'  => "",
> > >                  'State' => "",
> > >                  'Zip'   => ""
> > >     );
> > >
> > > Else %addr will be an empty hash, which I'm sure is not what you were
> > > expecting.
> > >
> > > Jim.
> > >
> > > Jim Lynch wrote:
> > > >
> > > > Hi, Chris,
> > > >
> > > > Try this:
> > > >
> > > > >     bless \%addr, 'Address';
> > > > >     return \%addr;
> > > > > }
> > > >
> > > > Christopher Fowler wrote:
> > > > >
> > > > > I'm going to solve my complex data structure issue with OOP.  Plus it
> > > > > will help out in the future.  I'm starting this but have ran into a
> > > > > sumple issue of not being able to call a method:
> > > > >
> > > > > I have the Perl Bookshelf and one example to do OOP is to use
> > > > > ObjectTemplate.  However Object Template is not in my distribution so
> > > > > I'm making an assumption that I can do OOP without using the template.
> > > > >
> > > > > --- Package --
> > > > > package Address;
> > > > > use strict;
> > > > >
> > > > > sub new {
> > > > >     my %addr = { 'Name' => "",
> > > > >                  'Line1' => "",
> > > > >                  'Line2' => "",
> > > > >                  'City'  => "",
> > > > >                  'State' => "",
> > > > >                  'Zip'   => ""
> > > > >     };
> > > > >
> > > > >     bless \%addr, 'Address';
> > > > >     return %addr;
> > > > > }
> > > > >
> > > > > sub test {
> > > > >     print "In test()\n";
> > > > > }
> > > > > # If I do not place a return 1 at the end, I get the
> > > > > # following error
> > > > > #
> > > > > #Address.pm did not return a true value at ./test line 4.
> > > > > #BEGIN failed--compilation aborted at ./test line 3.
> > > > >
> > > > > return 1;
> > > > >
> > > > > -- test.pl ---
> > > > >
> > > > > #!/usr/bin/perl
> > > > >
> > > > > use Address;
> > > > > use strict;
> > > > >
> > > > > my $addr = Address::new();
> > > > > $addr->test();
> > > > >
> > > > > --- Execution ---
> > > > > [cfowler at cfowler OOP]$ perl test
> > > > > Can't call method "test" without a package or object reference at test
> > > > > line 7.
> > > > > [cfowler at cfowler OOP]$
> > > > >
> > > > > ~
> > > > >
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