je::lvalue(3pm) [debian man page]

JE::LValue(3pm) 					User Contributed Perl Documentation					   JE::LValue(3pm)

NAME

       JE::LValue - JavaScript lvalue class

SYNOPSIS

	 use JE::LValue;

	 $lv = new JE::LValue $some_obj, 'property_name';

	 $lv->get;	   # get property
	 $lv->set($value)  # set property

	 $lv->some_other_method  # same as $lv->get->some_other_method

DESCRIPTION

       This class implements JavaScript lvalues (called "Reference Types" by the ECMAScript specification).

METHODS AND OVERLOADING

       If a method is called that is not listed here, it will be passed to the property referenced by the lvalue. (See the last item in the
       SYNOPSIS, above.) For this reason, you should never call "UNIVERSAL::can" on a JE::LValue, but, rather, call it as a method
       ("$lv->can(...)"), unless you really know what you are doing.

       Similarly, if you try to use an overloaded operator, it will be passed on to the object that the lvalue references, such that "!$lvalue" is
       the same as calling "!$lvalue->get".

       $lv = new JE::LValue $obj, $property
	   Creates an lvalue/reference with $obj as the base object and $property as the property name. If $obj is undefined or null, a TypeError
	   is thrown.  To create a lvalue that has no base object, and which will throw a ReferenceError when "->get" is called and create a
	   global property upon invocation of "->set", pass an unblessed reference to a global object as the first argument. (This is used by bare
	   identifiers in JS expressions.)

       $lv->get
	   Gets the value of the property.

       $lv->set($value)
	   Sets the property to $value and returns $value. If the lvalue has no base object, the global object will become its base object
	   automatically.  <Note:> Whether the lvalue object itself is modified in the latter case is not set in stone yet. (Currently it is
	   modified, but that may change.)

       $lv->call(@args)
	   If the property is a function, this calls the function with the base object as the 'this' value.

       $lv->base
	   Returns the base object. If there isn't any, it returns undef or an empty list, depending on context.

       $lv->property
	   Returns the property name.

perl v5.14.2							    2012-03-18							   JE::LValue(3pm)

UNIVERSAL(3pm)						 Perl Programmers Reference Guide					    UNIVERSAL(3pm)

NAME

       UNIVERSAL - base class for ALL classes (blessed references)

SYNOPSIS

	   $is_io = $fd->isa("IO::Handle");
	   $is_io = Class->isa("IO::Handle");

	   $sub = $obj->can("print");
	   $sub = Class->can("print");

	   use UNIVERSAL qw( isa can VERSION );
	   $yes = isa $ref, "HASH" ;
	   $sub = can $ref, "fandango" ;
	   $ver = VERSION $obj ;

DESCRIPTION

       "UNIVERSAL" is the base class which all bless references will inherit from, see perlobj.

       "UNIVERSAL" provides the following methods and functions:

       $obj->isa( TYPE ), CLASS->isa( TYPE ), isa( VAL, TYPE )
	       C<TYPE> is a package name
	       $obj is a blessed reference or a string containing a package name
	       C<CLASS> is a package name
	       C<VAL> is any of the above or an unblessed reference

	   When used as an instance or class method ("$obj-"isa( TYPE )>), "isa" returns true if $obj is blessed into package "TYPE" or inherits
	   from package "TYPE".

	   When used as a class method ("CLASS-"isa( TYPE )>; sometimes referred to as a static method), "isa" returns true if "CLASS" inherits
	   from (or is itself) the name of the package "TYPE" or inherits from package "TYPE".

	   When used as a function, like

	      use UNIVERSAL qw( isa ) ;
	      $yes = isa $h, "HASH";
	      $yes = isa "Foo", "Bar";

	   or

	      require UNIVERSAL ;
	      $yes = UNIVERSAL::isa $a, "ARRAY";

	   , "isa" returns true in the same cases as above and also if "VAL" is an unblessed reference to a perl variable of type "TYPE", such as
	   "HASH", "ARRAY", or "Regexp".

       $obj->can( METHOD ), CLASS->can( METHOD ), can( VAL, METHOD )
	   "can" checks if the object or class has a method called "METHOD". If it does then a reference to the sub is returned. If it does not
	   then undef is returned.  This includes methods inherited or imported by $obj, "CLASS", or "VAL".

	   "can" cannot know whether an object will be able to provide a method through AUTOLOAD, so a return value of undef does not necessarily
	   mean the object will not be able to handle the method call. To get around this some module authors use a forward declaration (see perl-
	   sub) for methods they will handle via AUTOLOAD. For such 'dummy' subs, "can" will still return a code reference, which, when called,
	   will fall through to the AUTOLOAD. If no suitable AUTOLOAD is provided, calling the coderef will cause an error.

	   "can" can be called as a class (static) method, an object method, or a function.

	   When used as a function, if "VAL" is a blessed reference or package name which has a method called "METHOD", "can" returns a reference
	   to the subroutine.  If "VAL" is not a blessed reference, or if it does not have a method "METHOD", undef is returned.

       VERSION ( [ REQUIRE ] )
	   "VERSION" will return the value of the variable $VERSION in the package the object is blessed into. If "REQUIRE" is given then it will
	   do a comparison and die if the package version is not greater than or equal to "REQUIRE".

	   "VERSION" can be called as either a class (static) method, an object method or or a function.

       These subroutines should not be imported via "use UNIVERSAL qw(...)".  If you want simple local access to them you can do

	 *isa = &UNIVERSAL::isa;

       to import isa into your package.

perl v5.8.0							    2002-06-01							    UNIVERSAL(3pm)