class::mix(3pm) [debian man page]

Class::Mix(3pm) 					User Contributed Perl Documentation					   Class::Mix(3pm)

NAME

       Class::Mix - dynamic class mixing

SYNOPSIS

	       use Class::Mix qw(mix_class);

	       $foobar_object = mix_class("Foo", "Bar")->new;

	       use Class::Mix qw(genpkg);

	       $package = genpkg;
	       $package = genpkg("Digest::Foo::");

DESCRIPTION

       The "mix_class" function provided by this module dynamically generates `anonymous' classes with specified inheritance.

FUNCTIONS

       mix_class(CLASSES ...)
	   This function is used to dynamically generate `anonymous' classes by mixing pre-existing classes.  This is useful where an incomplete
	   class requires use of a mixin in order to become instantiable, several suitable mixins are available, and it is desired to make the
	   choice between mixins at runtime.

	   The function takes as its argument list the desired @ISA list of the mixture class to be created; that is, a list of names of classes
	   to inherit from.  It generates a class with the specified inheritance, and returns its name.  The same class will be returned by
	   repeated invocations with the same class list.  The returned name may be used to call a constructor or other class methods of the mixed
	   class.

	   A class name must be returned because there is no such thing as an anonymous class in Perl.	Classes are referenced by name.  The names
	   that are generated by this function are unique and insignificant.  See "genpkg" below for more information.

	   If fewer than two classes to inherit from are specified, the function does not bother to generate a new class.  If only one class is
	   specified then that class is returned.  If no classes are specified then "UNIVERSAL" is returned.  This provides the desired
	   inheritance without creating superfluous classes.

	   This function relies on the classes it returns remaining unmodified in order to be returned by future invocations.  If you want to
	   modify your dynamically-generated `anonymous' classes, use "genpkg" (below).

       genpkg([PREFIX])
	   This function selects and returns a package name that has not been previously used.	The name returned is an ordinary bareword-form
	   package name, and can be used as the second argument to "bless" and in all other ways that package names are used.  The package is
	   initially empty.

	   The package names returned by this function are of a type that should not be used as ordinary fixed module names.  However, it is not
	   possible to entirely prevent a clash.  This function checks that the package name it is about to return has not already been used, and
	   will avoid returning such names, but it cannot guarantee that a later-loaded module will not create a clash.

	   PREFIX, if present, specifies where the resulting package will go.  It must be either the empty string (to create a top-level package)
	   or a bareword followed by "::" (to create a package under that name).  For example, "Digest::" could be specified to ensure that the
	   resulting package has a name starting with "Digest::", so that "Digest->new" will accept it as the name of a message digest algorithm.

SEE ALSO

       Class::Generate

AUTHOR

       Andrew Main (Zefram) <zefram@fysh.org>

COPYRIGHT

       Copyright (C) 2004, 2006, 2009 Andrew Main (Zefram) <zefram@fysh.org>

LICENSE

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

perl v5.10.1							    2010-03-24							   Class::Mix(3pm)

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Class::ErrorHandler(3pm)				User Contributed Perl Documentation				  Class::ErrorHandler(3pm)

NAME

       Class::ErrorHandler - Base class for error handling

SYNOPSIS

	   package Foo;
	   use base qw( Class::ErrorHandler );

	   sub class_method {
	       my $class = shift;
	       ...
	       return $class->error("Help!")
		   unless $continue;
	   }

	   sub object_method {
	       my $obj = shift;
	       ...
	       return $obj->error("I am no more")
		   unless $continue;
	   }

	   package main;
	   use Foo;

	   Foo->class_method or die Foo->errstr;

	   my $foo = Foo->new;
	   $foo->object_method or die $foo->errstr;

DESCRIPTION

       Class::ErrorHandler provides an error-handling mechanism that's generic enough to be used as the base class for a variety of OO classes.
       Subclasses inherit its two error-handling methods, error and errstr, to communicate error messages back to the calling program.

       On failure (for whatever reason), a subclass should call error and return to the caller; error itself sets the error message internally,
       then returns "undef". This has the effect of the method that failed returning "undef" to the caller. The caller should check for errors by
       checking for a return value of "undef", and calling errstr to get the value of the error message on an error.

       As demonstrated in the SYNOPSIS, error and errstr work as both class methods and object methods.

USAGE

       Class->error($message)

       $object->error($message)

       Sets the error message for either the class Class or the object $object to the message $message. Returns "undef".

       Class->errstr

       $object->errstr

       Accesses the last error message set in the class Class or the object $object, respectively, and returns that error message.

LICENSE

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

AUTHOR &; COPYRIGHT
       Except where otherwise noted, Class::ErrorHandler is Copyright 2004 Benjamin Trott, cpan@stupidfool.org. All rights reserved.

perl v5.8.7							    2005-07-20						  Class::ErrorHandler(3pm)

Linux and UNIX Man Pages

class::mix(3pm) [debian man page]

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