Graham Knop > Moo-1.004002 > Sub::Defer

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Module Version: 1.004002   Source   Latest Release: Moo-1.006000

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.

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