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".
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 v5.18.2 2013-12-31 Sub::Defer(3)