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



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".

   undefer_all
        undefer_all();

       This will undefer all defered subs in one go.  This can be very useful in a forking
       environment where child processes would each have to undefer the same subs.  By calling
       this just before you start forking children you can undefer all currently deferred subs in
       the parent so that the children do not have to do it.

SUPPORT
       See Moo for support and contact information.

AUTHORS
       See Moo for authors.

COPYRIGHT AND LICENSE
       See Moo for the copyright and license.



perl v5.20.1                                2014-10-22                            Sub::Defer(3pm)