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Module::Load

Perl 5 version 20.1 documentation
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Module::Load

NAME

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

SYNOPSIS

  1. use Module::Load;
  2. my $module = 'Data::Dumper';
  3. load Data::Dumper; # loads that module, but not import any functions
  4. # -> cannot use 'Dumper' function
  5. load 'Data::Dumper'; # ditto
  6. load $module # tritto
  7. autoload Data::Dumper; # loads that module and imports the default functions
  8. # -> can use 'Dumper' function
  9. my $script = 'some/script.pl'
  10. load $script;
  11. load 'some/script.pl'; # use quotes because of punctuations
  12. load thing; # try 'thing' first, then 'thing.pm'
  13. 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.

  1. load File::Spec::Functions, qw/splitpath/;
  2. 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.

    1. use Module::Load 'load_remote';
    2. my $pkg = 'Other::Package';
    3. load_remote $pkg, 'Data::Dumper'; # load a module to 'Other::Package'
    4. # 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.

    1. use Module::Load 'autoload_remote';
    2. my $pkg = 'Other::Package';
    3. autoload_remote $pkg, 'Data::Dumper'; # load a module to 'Other::Package'
    4. # 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.

    1. # imports 'load' and 'autoload' (default)
    2. use Module::Load;
    3. # imports 'autoload' only
    4. use Module::Load 'autoload';
    5. # imports 'autoload' and 'autoload_remote', but don't import 'load';
    6. use Module::Load qw/autoload autoload_remote/;
  • 'all'

    Imports all the functions.

    1. use Module::Load 'all'; # imports load, autoload, load_remote, autoload_remote
  • '','none',undef

    Not import any functions (load and autoload are not imported).

    1. use Module::Load '';
    2. use Module::Load 'none';
    3. 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 )

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.