Module::Load

Section: User Contributed Perl Documentation (3)
Updated: 2020-01-30
Page Index
 

NAME

Module::Load - runtime require of both modules and files  

SYNOPSIS

  use Module::Load;

  my $module = 'Data::Dumper';

  load Data::Dumper;     # loads that module, but not import any functions
                         # -> cannot use 'Dumper' function

  load 'Data::Dumper';   # ditto
  load $module           # tritto

  autoload Data::Dumper; # loads that module and imports the default functions
                         # -> can use 'Dumper' function

  my $script = 'some/script.pl'
  load $script;
  load 'some/script.pl';  # use quotes because of punctuations

  load thing;             # try 'thing' first, then 'thing.pm'

  load CGI, ':all';       # like 'use CGI qw[:standard]'

 

DESCRIPTION

"Module::Load" eliminates the need to know whether you are trying to require either a file or a module.

If you consult "perldoc -f require" you will see that "require" will behave differently when given a bareword or a string.

In the case of a string, "require" assumes you are wanting to load a file. But in the case of a bareword, it assumes you mean a module.

This gives nasty overhead when you are trying to dynamically require modules at runtime, since you will need to change the module notation ("Acme::Comment") to a file notation fitting the particular platform you are on.

"Module::Load" eliminates the need for this overhead and will just DWYM.  

Difference between load and autoload

"Module::Load" imports the two functions - "load" and "autoload"

"autoload" imports the default functions automatically, but "load" do not import any functions.

"autoload" is usable under "BEGIN{};".

Both the functions can import the functions that are specified.

Following codes are same.

  load File::Spec::Functions, qw/splitpath/;

  autoload File::Spec::Functions, qw/splitpath/;

 

FUNCTIONS

load
Loads a specified module.

See ``Rules'' for detailed loading rule.

autoload
Loads a specified module and imports the default functions.

Except importing the functions, 'autoload' is same as 'load'.

load_remote
Loads a specified module to the specified package.

  use Module::Load 'load_remote';

  my $pkg = 'Other::Package';

  load_remote $pkg, 'Data::Dumper'; # load a module to 'Other::Package'
                                    # but do not import 'Dumper' function

A module for loading must be quoted.

Except specifing the package and quoting module name, 'load_remote' is same as 'load'.

autoload_remote
Loads a specified module and imports the default functions to the specified package.

  use Module::Load 'autoload_remote';

  my $pkg = 'Other::Package';

  autoload_remote $pkg, 'Data::Dumper'; # load a module to 'Other::Package'
                                        # and imports 'Dumper' function

A module for loading must be quoted.

Except specifing the package and quoting module name, 'autoload_remote' is same as 'load_remote'.

 

Rules

All functions have the following rules to decide what it thinks you want:
If the argument has any characters in it other than those matching "\w", ":" or "'", it must be a file
If the argument matches only "[\w:']", it must be a module
If the argument matches only "\w", it could either be a module or a file. We will try to find "file.pm" first in @INC and if that fails, we will try to find "file" in @INC. If both fail, we die with the respective error messages.
 

IMPORTS THE FUNCTIONS

'load' and 'autoload' are imported by default, but 'load_remote' and 'autoload_remote' are not imported.

To use 'load_remote' or 'autoload_remote', specify at 'use'.

"load","autoload","load_remote","autoload_remote"
Imports the selected functions.

  # imports 'load' and 'autoload' (default)
  use Module::Load;

  # imports 'autoload' only
  use Module::Load 'autoload';

  # imports 'autoload' and 'autoload_remote', but don't import 'load';
  use Module::Load qw/autoload autoload_remote/;

'all'
Imports all the functions.

  use Module::Load 'all'; # imports load, autoload, load_remote, autoload_remote

'','none',undef
Not import any functions ("load" and "autoload" are not imported).

  use Module::Load '';

  use Module::Load 'none';

  use Module::Load undef;

 

Caveats

Because of a bug in perl (#19213), at least in version 5.6.1, we have to hardcode the path separator for a require on Win32 to be "/", like on Unix rather than the Win32 "\". Otherwise perl will not read its own %INC accurately double load files if they are required again, or in the worst case, core dump.

"Module::Load" cannot do implicit imports, only explicit imports. (in other words, you always have to specify explicitly what you wish to import from a module, even if the functions are in that modules' @EXPORT)  

SEE ALSO

Module::Runtime provides functions for loading modules, checking the validity of a module name, converting a module name to partial ".pm" path, and related utility functions.

``require'' in perlfunc <https://metacpan.org/pod/perlfunc#require> and ``use'' in perlfunc <https://metacpan.org/pod/perlfunc#use>.

Mojo::Loader is a ``class loader and plugin framework'', and is included in the Mojolicious <https://metacpan.org/release/Mojolicious> distribution.

Module::Loader is a module for finding and loading modules in a given namespace, inspired by "Mojo::Loader".  

ACKNOWLEDGEMENTS

Thanks to Jonas B. Nielsen for making explicit imports work.  

BUG REPORTS

Please report bugs or other issues to <bug-module-load@rt.cpan.org<gt>.  

AUTHOR

This module by Jos Boumans <kane@cpan.org>.  

COPYRIGHT

This library is free software; you may redistribute and/or modify it under the same terms as Perl itself.


 

Index

NAME
SYNOPSIS
DESCRIPTION
Difference between load and autoload
FUNCTIONS
Rules
IMPORTS THE FUNCTIONS
Caveats
SEE ALSO
ACKNOWLEDGEMENTS
BUG REPORTS
AUTHOR
COPYRIGHT
LinuxReviews : manual page archive : man3pm