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 { ... }, \%options;
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.
Exported by default.
Options
A hashref of options can optionally be specified.
package
The package to generate the sub in. Will be overridden by a fully
qualified $name option. If not specified, will default to the
caller's package.
attributes
The "Subroutine Attributes" in perlsub to apply to the sub
generated. Should be specified as an array reference.
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".
Exported by default.
defer_info
my $data = defer_info $sub;
my ($name, $generator, $options, $undeferred_sub) = @$data;
Returns original arguments to defer_sub, plus the undeferred version if
this sub has already been undeferred.
Note that $sub can be either the original deferred version or the
undeferred version for convenience.
Not exported by default.
undefer_all
undefer_all();
This will undefer all deferred subs in one go. This can be very useful
in a forking environment where child processes would each have to
undefer the same subs. By calling this just before you start forking
children you can undefer all currently deferred subs in the parent so
that the children do not have to do it. Note this may bake the
behavior of some subs that were intended to calculate their behavior
later, so it shouldn't be used midway through a module load or class
definition.
Exported by default.
undefer_package
undefer_package($package);
This undefers all deferred subs in a package.
Not exported by default.
SUPPORT
See Sub::Quote(3) for support and contact information.
AUTHORS
See Sub::Quote for authors.
COPYRIGHT AND LICENSE
See Sub::Quote for the copyright and license.
perl v5.30.0 2019-10-01 Sub::Defer(3)
sub-quote 2.6.6 - Generated Fri Jul 24 15:49:14 CDT 2020