If you don't mind the performance hit, try to access your hash keys through methods only. That way, if you change the the name of the key, you should only need to change it two or three times - once in the constructor, and once for get/set methods:

package Foo;

sub new {
   my $class = shift;
   my $self = {
      foo => 'bar',
      baz => 'qux',
   };
   return bless $self, $class;
}

# 'private' method
sub _get_foo {
   my $self = shift;
   return $self->{foo};
}

# 'public' method
sub get_foo {
   my $self = shift;
   return $self->_get_foo();
}
[download]

The 'private' accessor has to know the name of the hash key, but the 'public' accessor doesn't. So, if you change foo to bar:

# 'private' has to change
sub _get_foo {
    my $self = shift;
    return $self->{bar};
}

# but 'public' doesn't
sub get_foo {
    my $self = shift;
    return $self->_get_foo();
}
[download]

You don't have to track down as many places to change. There are still issues however, such as whether or not calling get_foo() to 'get bar' is acceptable. This is why proper feedback and designing is vital for large projects. However, as Murphy says, "Variables aren't. Constants don't". Also, i find it better to deprecate methods instead of outright removing/renaming them if you do have to change your interface accessor names:

sub get_foo {
   my $self = shift;
   carp "get_foo() is deprecated, use get_bar()";
   return _get_bar();
}

sub get_bar {
   my $self = shift;
   return $self->_get_bar();
}
[download]

Just some food for thought ...

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)