Re^2: Perl templating/macro creating using 'BEGIN'...

[perl-diddler]

The first 'main_package_vars' is in a BEGIN block because it is a duplicate of the one below it. I want to move the BEGIN block out of the package declaration and into the 'main' block.

Then I want to use the package_vars definition in 'main'. I.e. I started with a BEGIN block only in a package like this (which works, but doesn't work if I remove the BEGIN block as you seem(?) to be suggesting).

#!/usr/bin/perl  -w
use strict;
use feature ':5.10';

package MyPackage;
{
    BEGIN {
        sub package_vars {
            foreach(@_) {
                eval "sub $_ {
                    my \$p = shift;
                    \$p->{$_} = \$_[0] if \@_;
                    \$p->{$_};
                }"
            }
        }
    }

    package_vars( qw(one two three) );

    sub new {
        my $package=shift;
        my $parms=$_[0];
        
        my $this={};

        foreach(%$parms) {
            $this->{$_}=$parms->{$_};
        }

        bless $this, $package;
    }
}

package main;

my $p=new MyPackage({three => 3,});

$p->two(1);

printf "two=%d, three=%d\n",$p->two, $p->three;

Now I try moving the BEGIN block out of the package and into main (thus 'main_package_vars'), and import it's functionality into the local package.

That's the problem I'm trying to solve. How to have my subroutine definition for 'package_vars' in 'main', and use it from a package, like in this (which doesn't work because package_vars, isn't being 'called' in MyPackage, now that it's been moved to main).

#!/usr/bin/perl  -w
use strict;
use feature ':5.10';

BEGIN {
    sub package_vars {
        foreach(@_) {
            eval "sub $_ {
                my \$p = shift;
                \$p->{$_} = \$_[0] if \@_;
                \$p->{$_};
            }"
        }
    }
}


package MyPackage;
    *package_vars=\&main::package_vars;
{

    package_vars( qw(one two three) );

    sub new {
        my $package=shift;
        my $parms=$_[0];
        
        my $this={};

        foreach(%$parms) {
            $this->{$_}=$parms->{$_};
        }

        bless $this, $package;
    }
}

package main;

my $p=new MyPackage({three => 3,});

$p->two(1);

printf "two=%d, three=%d\n",$p->two, $p->three;

The first version I posted had samples of the routine package_vars in each location where I could try changing the line that says 'package_vars3( qw(one two three));' to a line without the '3', and, call the original working version, vs. attempts at trying some way to call the version of 'package_vars' that was moved to main.

Is that more clear?

[Corion]

Some of the steps you take are somewhat clear, but I'm really wondering about the goal you're trying to reach by these steps. To me, it really seems as if you're trying to duplicate the functionality of Class::Accessor. The usage of Class::Accessor would be:

package MyPackage;
use parent qw(Class::Accessor);
__PACKAGE__->mk_accessors(qw(two three));

package main;
use strict;
my $f = MyPackage->new({three => 3});
$f->two(1);
printf "two=%d, three=%d\n",$f->two, $f->three;

This seems to be your use case, so why reinvent the wheel?