Simple OO

[lzcd]

Ignoring complaints of cargo cult programming, can anybody shed light on why Perl doesn't seem to like this bit of code? It keeps looking for sheep.pm in the @INC and obviously not finding it.

package sheep;
use strict;

sub new {
        my $proto=shift;
        my $class=ref{$proto} || $proto;
        my $self={};
        bless($self,$class);
        return $self;
}

sub bleet {
        my $self=shift;
        return 'Baaaa!';
}

package main;
use strict;
use sheep; 

my wolf=new sheep;
print wolf->bleet()."\n";

[dws]

If this code fragment is really in a single file, then you don't need   use sheep; Since the 'sheep' package is already in the symbol table. use is a bit confusing that way. The argument refers to a file, not a package. You have to trust that the file being use'd actually defines a package of the same name.

[lzcd]

Without the use statement I get:

No such class wolf at demo.pl line 22, near "my wolf"
syntax error at demo.pl line 22, near "my wolf="

[Kanji]

You're missing some $'s ...

my $wolf=new sheep;
print $wolf->bleet()."\n";

    --k.

[dws]

Without the use statement I get:

No such class wolf at demo.pl line 22, near "my wolf"
syntax error at demo.pl line 22, near "my wolf="

The reason for this error message is a bit more obscure. (It has to do with something called "indirect object syntax".) However, the error goes away if turn the bareword wolf into the scalar $wolf.

  my $wolf=new sheep;
     ^

I suspect this is what you had in mind.

[Ryszard]

Add this to the top of your test script (before you "use sheep")

BEGIN {push @INC, <path to sheep.pm>}

Interestingly enuff I had what seems to be a similar recently.

HTH

[lzcd]

Once again, thank you all. I now have working sheep... err... yes.

[Biker]

Do you use warnings?
Do you use strict?

Update: Of course you use strict. It's in the code snippet. Doh.
What I really wanted to ask was about the warnings. The question about strict just went in there by habit. ;-)



---

Everything will go worng!

[lzcd]

Errr... yep to both.

[uwevoelker]

Shouldn't you use

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

Doesn't ref{$proto} return 'HASH'?

[mortis]

Minor point: don't use lowercase package names.

Rationale: pragmas are lower case - your package name might class with a future pragma. Which is one of the reasons all (most) of the modules on CPAN start with uppercase characters .