HTML::Mason::Component - Mason Component Class
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.".\n";
}
Mason uses the Component class to store components loaded into memory. Components come from three distinct sources:
<%def>
or <%method> tags.
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.
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.
<%attr> section.
<%method> section.
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:
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})) { ... }
<%flags> section and affect the behavior of the component.
Unlike attributes, flags values do not get inherited from parent components.
Returns true if this component was loaded from a source or object file.
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.
<%def>. Undefined for anonymous components.
autohandler in or above the component's directory.
Can be changed via the inherit flag.
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.
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.
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]".
The following methods apply only to file-based components (those loaded from source or object files). They return undef for other component types.