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Module::Load(3perl) Perl Programmers Reference Guide Module::Load(3perl)

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.
2020-06-07 perl v5.30.3