NAME 
src/pmc/class.pmc - defines a class
DESCRIPTION
This class implements the Class PMC, as outlined in docs/pdds/pdd15_objects.pod.
Class is not derived from any other PMC.
Structure
The Role PMC structure (Parrot_Role) consists of five items:
name- The name of the class -- a STRING. An empty STRING is allocated during initialization.
namespace- The namespace the class is associated with, if any. A Null PMC is allocated during initialization.
instantiated- A flag denoting whether this class has been instantiated since last modification. A native integer with value zero is allocated during initialization.
parents- An array of immediate parent classes. An empty ResizablePMCArray PMC is allocated during initialization.
all_parents- A cached array of ourself and all parent classes, in MRO order. A ResizablePMCArray PMC is allocated during initialization, and is populated with the current class.
roles- An array of the roles this class has been composed from. An empty ResizablePMCArray PMC is allocated during initialization.
methods- A directory of method names and method bodies this class provides. An empty Hash PMC is allocated during initialization.
vtable_methods- A directory of vtable method names and method bodies this class overrides. An empty Hash PMC is allocated during initialization.
attrib_metadata- A directory of attribute names and attribute metadata this class contains. An empty Hash PMC is allocated during initialization.
attrib_index- A lookup table for attributes in this class and parents. A Null PMC is allocated during initialization.
attrib_cache- A cache of visible attribute names to attribute indexes. A Null PMC is allocated during initialization.
resolve_method- A list of method names the class provides used for name conflict resolution. An empty ResizablePMCArray PMC is allocated during initialization.
Functions
void init()- Initializes a Class PMC.
void init_pmc(PMC *name)- The actual class creation code,
called from
newclassopcode. Theinitargument must stringify to the name of the class. The class is attatched to the current namespace. PMC *subclass(PMC *name)- Creates a subclass,
optionally with a given
name. void destroy()- Free the memory associated with the object's underlying struct.
STRING *get_string()- Return the fully qualified name of the class.
void mark()- Mark any referenced strings and PMCs in the structure as live.
void add_attribute(STRING *name, PMC *type)- Adds the given attribute (
name) with an optionaltype. Creates a new class if the current class has been instantiated. Enters the attribute in theattributesarray. Returns an error if an attribute ofnamealready exists. void add_method(STRING *name, PMC *sub)- Adds the given sub PMC as a method with the given name.
void add_parent(PMC *parent)- Adds the supplied PMC to the list of parents for the class.
void add_role(PMC *role)- Adds the supplied PMC to the list of roles for the class, provided there are no conflicts.
PMC *inspect_str(STRING *what)- Provides introspection of a specific piece of information about the class. The available information is:
- name
- String PMC containing the name of the class
- namespace
- NameSpace PMC of the the namespace attached to the class
- attributes
- Hash keyed on attribute name, value is hash describing it
- methods
- Hash keyed on method name, value is an invokable PMC. Includes methods composed in from roles.
- roles
- Array of Role PMCs. Includes roles done by the roles that were composed into this class.
- parents
- Array of Class PMCs representing the direct parents of this class.
PMC *inspect()- Returns a Hash describing the class, with key/value pairs as described in inspect_str.
PMC *clone()- Returns an anonymous copy of the class (with no name and no link to a namespace). Unsets the instantiated flag, allowing modifications.
PMC *clone_pmc(PMC *args)- Makes a copy of the class,
then modifies or adds to it based upon the contents of the supplied initialization data.
If a new name or namespace is not supplied in
argsthen the cloned class will be anonymous. The instantiated flag is unset to allow further modifications. INTVAL isa(STRING *classname)- Returns whether the class is or inherits from
*classname. void name(STRING *name :optional, int got_name :opt_flag)- Sets the name of the class, and updates the namespace accoringly.
void pmc_namespace()- Gets the namespace that this class is attached to.
void resolve_method()- Sets the list of method names that the class provides to resolve conflicts in methods from roles. When called with no parameter, returns the list.
void new(PMC *args :slurpy :named)- Creates an instance of the object. Initializes any attributes specified in the parameter list.
void attributes()- Return a hash where the keys are attribute names and the values are hashes providing a set of key/value pairs describing the attribute.
void add_attribute()- Add an attribute to the class. Requires a name and, optionally, a type.
void methods()- Return a hash where the keys are method names and the values are methods.
void add_method(STRING *name, PMC *sub)- Adds the given sub PMC as a method with the given name.
Delegates to the
add_methodvtable method. PMC *find_method(STRING *name)- Walks the MRO of the class and finds the method with the given name.
- */
- /*
void parents()- Return the parents array PMC.
void add_parent(PMC *parent)- Adds the supplied PMC to the list of parents for the class.
void roles()- Return the roles array PMC.
void add_role(PMC *role, PMC *exclude :optional :named["exclude"], PMC *alias :optional :named["alias"])- Compose a role into a class with the given exclusions and aliases.
void inspect(STRING *what :optional)- Gets all introspection data for the class or, if the optional string parameter is supplied, a particular item of introspection data.
void isa(STRING *class_name)- Returns true if this object is or derives from the class named in
class_name, false otherwise. void does(STRING *role_name)- Returns true if this object or one of its parents performs the named role, false otherwise.
PCCMETHOD void find_method(STRING *name) {
Parrot_Class * const _class = PARROT_CLASS(SELF);
PMC *namespace = _class->_namespace;
int num_classes, i;
if ( ! PMC_IS_NULL(namespace)
&& VTABLE_exists_keyed_str(interp, namespace, name)) {
PMC *ret = VTABLE_get_pmc_keyed_str(interp, namespace, name);
PCCRETURN(PMC *ret);
}
/* Walk and search. One day, we'll use the cache first. */
num_classes = VTABLE_elements(interp, _class->all_parents);
for (i = 0; i < num_classes; i++) {
/* Get the class and see if it has the method. */
PMC * const cur_class =
VTABLE_get_pmc_keyed_int(interp, _class->all_parents, i);
const Parrot_Class * const class_info = PARROT_CLASS(cur_class);
/* Found it! */
if (VTABLE_exists_keyed_str(interp, class_info->methods, name)) {
PMC *ret = VTABLE_get_pmc_keyed_str(interp, class_info->methods,
name);
PCCRETURN(PMC *ret);
}
}
PCCRETURN(PMC *PMCNULL);
}
