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KIMOTO / SPVM-0.990056 / lib / SPVM / EqualityChecker.pm 

            

              
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package SPVM::EqualityChecker;
1;
=head1 Name
SPVM::EqualityChecker - Interface Type for Object Equality Checking Callback
=head1 Usage
   
  use EqualityChecker;
  use Point;
   
  my $equality_checker = (EqualityChecker)method : int ($object1 : object, $object2 : object) {
    my $point1 = (Point)$object1;
    my $point2 = (Point)$object2;
     
    if ($point1->x == $point2->x && $point1->y == $point2->y) {
      return 1;
    }
    else {
      return 0;
    }
  };
   
  my $point1 = Point->new(1, 2);
  my $point2 = Point->new(5, 6);
   
  my $is_equal = $equality_checker->($point1, $point2);
=head1 Description
L<EqualityChecker|SPVM::EqualityChecker> is the interface type for the object equality checking callback.
=head1 Interface Methods
C<required method : int ($object1 : object, $object2 : object)>
The implementation must receive two objects and if they are equal, return 1. Otherwise, return 0.
=head1 Class Methods
=head2 default_equality_checker
C<static method default_equality_checker : L<EqualityChecker|SPVM::EqualityChecker> ();>
Returns a default default equality checker.
The implementation of the default equality checker is
  method : int ($object1 : EqualityCheckable, $object2 : EqualityCheckable) {
     
    my $eq = 0;
    if ($object1 && $object2) {
      $eq = $object1->eq($object1, $object2);
    }
    elsif ($object1) {
      $eq = 0;
    }
    elsif ($object2) {
      $eq = 0;
    }
    else {
      $eq = 1;
    }
     
    return $eq;
  };
If $object1 and $object2 are defined, the check of equality is perfermed by L<EqualityCheckable#eq|SPVM::EqualityCheckable/"eq"> method in the class of $object1, and returns its return value.
If only $object1 is defined, returns 0.
If only $object2 is defined, returns 0.
If both $object1 and $object2 are not defined, returns 1.
=head1 Copyright & License
Copyright (c) 2023 Yuki Kimoto
MIT License