What is the use of getter and setter

lakshmananindia has asked for the wisdom of the Perl Monks concerning the following question:

Hai I want to know what is the use of getters and setters. I faced this when I am reading Archive::Tar. I can understand the code. But I cannot relate and what is the actual use and what are the alternatives.

my $tmpl = {
    _data   => [ ],
    _file   => 'Unknown',
};

for my $key ( keys %$tmpl ) {
    no strict 'refs';
    *{__PACKAGE__."::$key"} = sub {
        my $self = shift;
        $self->{$key} = $_[0] if @_;
        return $self->{$key};
    }
}
[download]

Comment on What is the use of getter and setter Download Code

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Re: What is the use of getter and setter by ikegami (Patriarch) on Nov 19, 2008 at 09:21 UTC
They hide the internal structure of the object from the caller. This allows the internal structure to be changed without breaking a lot of unrelated code. This is called encapsulation. For example, instead of doing `$obj->{key} = 'val';` [download] you'd do `$obj->key('val');` [download] The latter might simply do the same thing as the former. Or maybe it adds error checking. At the very least, it gives the option to add error checking without breaking code.	[reply] [d/l] [select]
Re: What is the use of getter and setter by Anonymous Monk on Nov 19, 2008 at 09:17 UTC
The comment that goes with the code says `### install get/set accessors for this object.` [download] http://en.wikipedia.org/wiki/Accessor In computer science, a mutator method is a method used to control changes to a variable. The mutator method, sometimes called a "setter", is most often used in object-oriented programming, in keeping with the principle of encapsulation. ... getters get values, setters set values, understand?	[reply] [d/l]
Re: What is the use of getter and setter by massa (Hermit) on Nov 19, 2008 at 10:11 UTC
Please, please... use <code> tags!!! []s, HTH, Massa (κς,πμ,πλ)	[reply]
Re^2: What is the use of getter and setter by Anonymous Monk on Nov 19, 2008 at 14:39 UTC
`if( not $node->hascode ){ $massa->msg( $node->author, "use <code> tags!!!"); $massa->satisfaction('+1'); }` [download]	[reply] [d/l]