HTML::Mason::Component(3pm)				User Contributed Perl Documentation			       HTML::Mason::Component(3pm)

NAME

       HTML::Mason::Component - Mason Component Class

SYNOPSIS

	   my $comp1 = $m->current_comp;
	   my $comp2 = $m->callers(1);
	   my $comp3 = $m->fetch_comp('foo/bar');

	   foreach ($comp1,$comp2,$comp3) {
	      print "My name is ".$_->title.".
";
	   }

DESCRIPTION

       Mason uses the Component class to store components loaded into memory. Components come from three distinct sources:

       1.  File-based: loaded from a source or object file.

       2.  Subcomponents: embedded components defined with the "<%def>" or "<%method>" tags.

       3.  Anonymous: created on-the-fly with the "make_component" Interp method.

       Some of the methods below return different values (or nothing at all) depending on the component type.

       The component API is primarily useful for introspection, e.g. "what component called me" or "does the next component take a certain
       argument".  You can build complex Mason sites without ever dealing directly with a component object.

   CREATING AND ACCESSING COMPONENTS
       Common ways to get handles on existing component objects include the Request->current_comp, Request->callers, and Request->fetch_comp
       methods.

       There is no published "new" method, because creating a component requires an Interpreter. Use the make_component method to create a new
       component dynamically.

       Similarly, there is no "execute" or "call" method, because calling a component requires a request. All of the interfaces for calling a
       component ("<& &>", "$m->comp", "$interp->exec") which normally take a component path will also take a component object.

METHODS

       attr (name)
	   Looks for the specified attribute in this component and its parents, returning the first value found. Dies with an error if not found.
	   Attributes are declared in the "<%attr>" section.

       attr_if_exists (name)
	   This method works exactly like the one above but returns undef if the attribute does not exist.

       attr_exists (name)
	   Returns true if the specified attribute exists in this component or one of its parents, undef otherwise.

       attributes
	   Returns a hashref containing the attributes defined in this component, with the attribute names as keys.  This does not return
	   attributes inherited from parent components.

       call_method (name, args...)
	   Looks for the specified user-defined method in this component and its parents, calling the first one found. Dies with an error if not
	   found.  Methods are declared in the "<%method>" section.

       create_time
	   A synonym for load_time (deprecated).

       declared_args
	   Returns a reference to a hash of hashes representing the arguments declared in the "<%args>" section. The keys of the main hash are the
	   variable names including prefix (e.g. $foo, @list). Each secondary hash contains:

	   o   'default': the string specified for default value (e.g. 'fido') or undef if none specified.  Note that in general this is not the
	       default value itself but rather a Perl expression that gets evaluated every time the component runs.

	   For example:

	     # does $comp have an argument called $fido?
	     if (exists($comp->declared_args->{'$fido'})) { ... }

	     # does $fido have a default value?
	     if (defined($comp->declared_args->{'$fido'}->{default})) { ... }

       dir_path
	   Returns the component's notion of a current directory, relative to the component root; this is used to resolve relative component
	   paths. For file-based components this is the full component path minus the filename.  For subcomponents this is the same as the
	   component that defines it.  Undefined for anonymous components.

       flag (name)
	   Returns the value for the specified system flag.  Flags are declared in the "<%flags>" section and affect the behavior of the
	   component.  Unlike attributes, flags values do not get inherited from parent components.

       is_subcomp
	   Returns true if this is a subcomponent of another component.  For historical reasons, this returns true for both methods and
	   subcomponents.

       is_method
	   Returns true if this is a method.

       is_file_based
	   Returns true if this component was loaded from a source or object file.

       load_time
	   Returns the time (in Perl time() format) when this component object was created.

       method_exists (name)
	   Returns true if the specified user-defined method exists in this component or one of its parents, undef otherwise.

       methods
	   This method works exactly like the subcomps method, but it returns methods, not subcomponents.  This does not return methods inherited
	   from parent components.

	   Methods are declared in "<%method>" sections.

       name
	   Returns a short name of the component.  For file-based components this is the filename without the path. For subcomponents this is the
	   name specified in "<%def>". Undefined for anonymous components.

       object_file
	   Returns the object filename for this component.

       parent
	   Returns the parent of this component for inheritance purposes, by default the nearest "autohandler" in or above the component's
	   directory.  Can be changed via the "inherit" flag.

       path
	   Returns the entire path of this component, relative to the component root.

       scall_method (name, args...)
	   Like item_call_method, but returns the method output as a string instead of printing it. (Think sprintf versus printf.) The method's
	   return value, if any, is discarded.

       subcomps
	   With no arguments, returns a hashref containing the subcomponents defined in this component, with names as keys and component objects
	   as values.  With one argument, returns the subcomponent of that name or undef if no such subcomponent exists. e.g.

	       if (my $subcomp = $comp->subcomps('.link')) {
		   ...
	       }

	   Subcomponents are declared in "<%def>" sections.

       title
	   Returns a printable string denoting this component.	It is intended to uniquely identify a component within a given interpreter
	   although this is not 100% guaranteed. Mason uses this string in error messages, among other places.

	   For file-based components this is the component path.  For subcomponents this is "parent_component_path:subcomponent_name". For
	   anonymous components this is a unique label like "[anon 17]".

FILE-BASED METHODS
       The following methods apply only to file-based components (those loaded from source or object files). They return undef for other component
       types.

       source_file
	   Returns the source filename for this component.

       source_dir
	   Returns the directory of the source filename for this component.

SEE ALSO

       HTML::Mason, HTML::Mason::Devel, HTML::Mason::Request

perl v5.14.2							    2012-02-04					       HTML::Mason::Component(3pm)