Re: how to avoid mis-spelling hash keys?

[FamousLongAgo]

in reply to how to avoid mis-spelling hash keys?

Another tack is to wrap the attributes in accessor methods. E.g,

sub get_attr { $_[0]->{'attr'} }
sub set_attr { $_[0]->{'attr'} = $_[1] }

Now if you misspell an attribute name, it gives you a run-time error.

Some people hate this approach and call it monkey code, I like it because it documents the object's interface, and lets you change the internal implementation away from a hash if you like. If you really hate writing accessors, consider Class::MethodMaker.

Whatever else, Damian Conway's book (cited above) is invaluable for OO Perl.

[crouchingpenguin]

I like to use AUTOLOAD for my accessors like:

sub AUTOLOAD {
  my $self = shift;
  return unless ref($self);
    
  # lets find out what the mysterious missing func is
  my ($attribute) = $AUTOLOAD =~ m/.*::(.*)/;

  # this is our psuedo get/set
  # we can make this as simple or complex as we want
  if( my $value = shift ){ ### we have an argument

    # if attribute exists
    # this is our sort of rudimentary access control
    # so we can't create arbitrary attributes
    if( exists $self->{$attribute} ){
      $self->{$attribute} = $value;
    }elsif( exists $self->{ lc($attribute) } ){
      # double check caller didn't mean lower case
      $self->{ lc($attribute) } = $value;
    }else{
      # we can put assignment code here if 
      # we want to be able to automatically
      # create object attributes on the fly
    }
    # here is a good place to call your commit()
    # or write() method if applicable
    $self->write();
  }else{ # must be an get type call
    return $self->{$attribute} if exists $self->{$attribute};
    return $self->{lc($attribute)} if exists $self->{lc($attribute)};
  }# end if/elsif/else value = shift 
}


Update: BrentDax is spot on

"Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic."

[BrentDax]

   if( $self­->{$a­ttrib­ute} ){

That will fail if $self->{$attribute} is set to zero, the empty string, or undef. Perhaps this would work better:

   if(exists $self->{$attribute}) {

=cut
--Brent Dax
There is no sig.