Mastering Modern Perl: Writing Efficient and Maintainable Code/

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AUTOLOAD

AUTOLOAD

Learn about the AUTOLOAD function and how it handles undeclared functions.

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Calling undeclared functions

Perl doesn’t require us to declare every function before we call it. Perl will happily attempt to call a function even if it doesn’t exist. Consider this program:

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use Modern::Perl;
bake_pie( filling => 'apple' );

When we run it, Perl will throw an exception due to the call to the undefined function bake_pie().

Now, we’ll add a function called AUTOLOAD():

sub AUTOLOAD {}

Now when we run the program, nothing obvious will happen. Perl will call a function named AUTOLOAD() in a package—if it exists—whenever normal dispatch fails. Change the ...