Tutorial Addendum on Perl - Allotment A - perlobj - Perl Altar

Output:

    

 

    
Test 1:

    
   Param #1 = Jan

    
   Param #2 = Feb

    
Test 2:

    
   Param #1 = Apple

    
   Param #2 = Banana

    
Test 3:

    
   Param #1 = One

    
   Param #2 = Two

    
Test 4:

    
   Param #1 = Foo

    
   Param #2 = Cow

    
   Param #3 = Horse

    
Test 7:

    
   Param #1 = Foo

    
   Param #2 = Monday

    
   Param #3 = Tuesday

    

Note that:

    

    
• Tests 1, 2 and 3 are accustomed means to adjure a subroutine in a package.
  
      



    
• Tests 4 and 7 are appropriate means to adjure a subroutine as a chic method.
  
      



    
• Test 5 is wrong, because "&" is not allowed.
  
      



    
• Tests 6 and 8 are wrong, because "Bar" is not accustomed as a chic (package).
  
      



    

Invoking Amalgamation Subroutines as Item Methods

    

In adjustment to use references (hard references, not bendable references) as

    

objects of a class, we charge to accessory references with a chic first.

    

This is done by using the bless() funtion in one of the afterward syntaxes:

    

    
   $rc = bless($reference, class_name);

    
   $rc = bless($reference);

    

where "$reference" is a advertence of any data type, which will be associated with

    

the defined "class_name" (package name). "$rc" is the abiding archetype of

    

the aforementioned reference. If "class_name" is omitted, the accepted amalgamation name will

    

be acclimated as the chic name.

    

Perl object - A advertence that has been adored with a amalgamation name.

    

To amount out the associated chic name of object, you can use the ref() function:

    

    
   $rc = ref($object);

    

Similar to chic adjustment invocation, if a subroutine is invoked as an object

    

method, the item (blessed reference) will be automatically amid into

    

the altercation account as the first argument.

    

There are two way to adjure a subroutine as a chic method:

    

1. Using the "indirect object" syntax:

    

    
   sub_identifier $object arg2, arg3, ...

    

where "sub_identifier" is the subroutine identifier after any amalgamation name prefixes

    

and "&";

    

"$object" is a adored object; and

    

"arg2, arg3, ..." is the altercation account

    

starting from the additional altercation after parentheses.

    

2. Using the "->" notation:

    

    
   $object->sub_identifier(arg2, arg3, ...)

    

where "sub_identifier" is the subroutine identifier after any amalgamation name prefixes

    

and "&";

    

"$object" is a adored object; and "arg2, arg3, ..." is the altercation account

    

starting from the additional argument. In this format, parentheses on the argument

    

list are optional.