Proper use of AUTOLOAD

I would like to immediately warn: This article is not intended for bison, but describes quite a common trick with AUTOLOAD.

Introduction

Perl has a great opportunity to work out calls to undefined methods.
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For example, in the case of

package Something; our $AUTOLOAD; sub AUTOLOAD { return 'any data'; } sub DESTROY { } package XTest; my $o = new Something(); print $o->dry(); 

The result will be 'any data'.

disadvantages

The disadvantage of this method is actually one - poor performance with repeated calls.

Method generation on the fly

This behavior will be fixed by generating methods on the fly.

 package Something; our $AUTOLOAD; sub AUTOLOAD { my ($self) = @_; my $name = $AUTOLOAD; return if $name =~ /^.*::[AZ]+$/; $name =~ s/^.*:://; # strip fully-qualified portion my $sub = sub { my $self = shift(); return 'any data'; }; no strict 'refs'; *{$AUTOLOAD} = $sub; use strict 'refs'; goto &{$sub}; } package XTest; my $o = new Something(); print $o->dry(); 

Where is it useful

In addition to all sorts of custom accessors (I sincerely recommend Class :: Accessor :: Fast, where possible), it is often useful for writing wrappers around objects that cannot be inherited (for example, you need a hash, and the object is an XS handle).

Performance

Judging by the Benchmark package, creating an object and a 100-fold invoking an unknown method on the server (FreeBSD / x64 / Perl5.8.8) gives in the first case up to 3400 calls per second, and up to 11000 calls per second in the second case. Speed ​​grows three times.