BEGIN { package class_vars; use strict; use warnings; sub import { shift; my $pkg = caller; for my $var (@_) { eval(" package $pkg; use vars '\$$var'; sub $var { \$$var = \$_[1] if \@_ > 1; return \$$var; } "); } } $INC{'class_vars.pm'} = __FILE__; } { package MyPackage; use strict; use warnings; use class_vars qw( one two three ); sub init_one_from_three { $one=$three-2; } sub new { my $package=shift; my $parms=$_[0]; my $this={}; foreach(keys %$parms) { no strict 'refs'; $$_=$parms->{$_}; } bless $this, $package; } } { use strict; use warnings; my $p=new MyPackage({three => 3,}); $p->two(2); $p->init_one_from_three; printf "one=%d two=%d, three=%d\n", $p->one, $p->two, $p->three; }