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Class-Refresh-0.01
River stage one • 3 direct dependents • 3 total dependents
1 ++
/ Class::Refresh

NAME

Class::Refresh - refresh your classes during runtime

VERSION

version 0.01

SYNOPSIS

  use Class::Refresh;
  use Foo;

  Class::Refresh->refresh;

  # edit Foo.pm

  Class::Refresh->refresh; # changes in Foo.pm are applied

DESCRIPTION

During development, it is fairly common to cycle between writing code and testing that code. Generally the testing happens within the test suite, but frequently it is more convenient to test things by hand when tracking down a bug, or when doing some exploratory coding. In many situations, however, this becomes inconvenient - for instance, in a REPL, or in a stateful web application, restarting from the beginning after every code change can get pretty tedious. This module allows you to reload your application classes on the fly, so that the code/test cycle becomes a lot easier.

This module has several limitations, due to reloading modules in this way being an inherently fragile operation. Therefore, this module is recommended for use only in development environments - it should not be used for reloading things in production.

It makes several assumptions about how code is structured that simplify the logic involved quite a bit, and make it more reliable when those assumptions hold, but do make it inappropriate for use in certain cases. For instance, this module is named Class::Refresh for a reason: it is only intended for refreshing classes, where each file contains a single namespace, and each namespace corresponds to a single file, and all function calls happen through method dispatch. Unlike Module::Refresh, which makes an effort to track the files where subs were defined, this module assumes that refreshing a class means wiping out everything in the class's namespace, and reloading the file corresponding to that class. If your code includes multiple files that all load things into a common namespace, or defines multiple classes in a single file, this will likely not work.

METHODS

refresh

The main entry point to the module. The first call to refresh populates a cache of modification times for currently loaded modules, and subsequent calls will refresh any classes which have changed since the previous call.

modified_modules

Returns a list of modules which have changed since the last call to refresh.

refresh_module $mod

This method calls unload_module and load_module on $mod, as well as on any classes that depend on $mod (for instance, subclasses if $mod is a class, or classes that consume $mod if $mod is a role). This ensures that all of your classes are consistent, even when dealing with things like immutable Moose classes.

unload_module $mod

Unloads $mod, using Class::Unload.

load_module $mod

Loads $mod, using Class::Load.

CAVEATS

Global variable accesses and function calls may not work as expected

Perl resolves accesses to global variables and functions in other packages at compile time, so if the package is later reloaded, changes to those will not be noticed. As mentioned above, this module is intended for refreshing classes.

File modification times have a granularity of one second

If you modify a file and then immediately call refresh and then immediately modify it again, the modification may not be seen on the next call to refresh. Note however that file size and inode number are also compared, so it still may be seen, depending on if either of those two things changed.

Tracking modules which use a given module isn't possible

For instance, modifying a Moose::Exporter module which is used in a class won't cause the class to be refreshed, even if the change to the exporter would cause a change in the class's metaclass.

Classes which build themselves differently based on the state of other classes may not work properly

This module attempts to handle several cases of this sort for Moose classes (modifying a class will refresh all of its subclasses, modifying a role will refresh all classes and roles which consume that role, modifying a metaclass will refresh all classes whose metaclass is an instance of that metaclass), but it's not a problem that's solvable in the general case.

CREDITS

This module was based in large part on Module::Refresh by Jesse Vincent.

BUGS

Reloading classes when their metaclass is modified doesn't quite work yet

This will require modifications to Moose to support properly.

Tracking changes to metaclasses other than the class metaclass isn't implemented yet
Metacircularity probably has issues

Refreshing a class which is its own metaclass will likely break.

Please report any bugs through RT: email bug-class-refresh at rt.cpan.org, or browse to http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Class-Refresh.

SEE ALSO

Please see those modules/websites for more information related to this module.

SUPPORT

You can find this documentation for this module with the perldoc command.

    perldoc Class::Refresh

You can also look for information at:

AUTHOR

Jesse Luehrs <doy at tozt dot net>

COPYRIGHT AND LICENSE

This software is copyright (c) 2011 by Jesse Luehrs.

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