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Sub::Defer(3)                        User Contributed Perl Documentation                       Sub::Defer(3)



NAME
       Sub::Defer - defer generation of subroutines until they are first called

SYNOPSIS
        use Sub::Defer;

        my $deferred = defer_sub 'Logger::time_since_first_log' => sub {
           my $t = time;
           sub { time - $t };
        };

         Logger->time_since_first_log; # returns 0 and replaces itself
         Logger->time_since_first_log; # returns time - $t

DESCRIPTION
       These subroutines provide the user with a convenient way to defer creation of subroutines and methods
       until they are first called.

SUBROUTINES
   defer_sub
        my $coderef = defer_sub $name => sub { ... };

       This subroutine returns a coderef that encapsulates the provided sub - when it is first called, the
       provided sub is called and is -itself- expected to return a subroutine which will be goto'ed to on
       subsequent calls.

       If a name is provided, this also installs the sub as that name - and when the subroutine is
       undeferred will re-install the final version for speed.

   undefer_sub
        my $coderef = undefer_sub \&Foo::name;

       If the passed coderef has been deferred this will "undefer" it.  If the passed coderef has not been
       deferred, this will just return it.

       If this is confusing, take a look at the example in the "SYNOPSIS".



perl v5.16.2                                     2012-07-04                                    Sub::Defer(3)