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Re^3: Can you override lexically scoped variables when sub-classing a module.

by jandrew (Hermit)
on Oct 11, 2012 at 20:28 UTC ( #998536=note: print w/ replies, xml ) Need Help??


in reply to Re^2: Can you override lexically scoped variables when sub-classing a module.
in thread Can you override lexically scoped variables when sub-classing a module.

Well if you can change the 'my' to 'our' in p1 then this works

Package 1

package p1; our $var1 = 'var1-p1';#Note the change my->our sub new { my $class = ref $_[0] ? ref shift : shift; my $self = {}; bless $self, $class; return $self; } sub get_var1 { return $var1; } 1;

Package 2

package p2; use p1; our @ISA=qw(p1); sub set_var1 { my $self = shift; my $new_var1 = shift; $p1::var1 = $new_var1; return $p1::var1; } 1;

You get a global variable that you may not want


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Re^4: Can you override lexically scoped variables when sub-classing a module.
by Anonymous Monk on Oct 11, 2012 at 20:45 UTC

    You only need to change my $var1 ... to our $var1 ... and adapt p2, but maybe your real p1-module is much more complicated?

    The patch of p2.pm below seems to work without changing p1.pm on disk, but I wouldn't recommend it for production.

    Rather try to fix the root problem, e.g. ask the module author or use a private modified copy of the module and use use lib or $PERL5LIB so the patched version is found first.

    #-- p1 not changed on disk ;-) use File::Slurp; my $text = read_file( 'p1.pm' ) ; $text =~ s/^\s*my(\s+\$var1)/our$1/ms; eval $text; #-- above not recommended! package p2; # use p1; our @ISA=qw(p1); sub set_var1 { my $self = shift; my $new_var1 = shift; # $var1 = $new_var1; # return $var1; $p1::var1 = $new_var1; return $p1::var1; } 1;

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