table of contents
Module::Load(3) | User Contributed Perl Documentation | Module::Load(3) |
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>.
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.
2020-09-29 | perl v5.32.1 |