Sub::Exporter::ForMethods(3) User Contributed Perl Documentation Sub::Exporter::ForMethods(3)

Sub::Exporter::ForMethods - helper routines for using Sub::Exporter to build methods

version 0.100052

In an exporting library:

  package Method::Builder;
  use Sub::Exporter::ForMethods qw(method_installer);
  use Sub::Exporter -setup => {
    exports   => [ method => \'_method_generator' ],
    installer => method_installer,
  };
  sub _method_generator {
    my ($self, $name, $arg, $col) = @_;
    return sub { ... };
  };

In an importing library:

  package Vehicle::Autobot;
  use Method::Builder method => { -as => 'transform' };

The synopsis section, above, looks almost indistinguishable from any other use of Sub::Exporter, apart from the use of "method_installer". It is nearly indistinguishable in behavior, too. The only change is that subroutines exported from Method::Builder into named slots in Vehicle::Autobot will be wrapped in a subroutine called "Vehicle::Autobot::transform". This will insert a named frame into stack traces to aid in debugging.

More importantly (for the author, anyway), they will not be removed by namespace::autoclean. This makes the following code work:

  package MyLibrary;
  use Math::Trig qw(tan);         # uses Exporter.pm
  use String::Truncate qw(trunc); # uses Sub::Exporter's defaults
  use Sub::Exporter::ForMethods qw(method_installer);
  use Mixin::Linewise { installer => method_installer }, qw(read_file);
  use namespace::autoclean;
  ...
  1;

After MyLibrary is compiled, "namespace::autoclean" will remove "tan" and "trunc" as foreign contaminants, but will leave "read_file" in place. It will also remove "method_installer", an added win.

Sub::Exporter::ForMethods offers only one routine for export, and it may also be called by its full package name:

  my $installer = method_installer(\%arg);

This routine returns an installer suitable for use as the "installer" argument to Sub::Exporter. It updates the "\@to_export" argument to wrap all code that will be installed by name in a named subroutine, then passes control to the default Sub::Exporter installer.

The only argument to "method_installer" is an optional hashref which may contain a single entry for "rebless". If the value for "rebless" is true, when a blessed subroutine is wrapped, the wrapper will be blessed into the same package.

Ricardo Signes <rjbs@cpan.org>

This software is copyright (c) 2015 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

2015-07-17 perl v5.34.0