I was just starting to port Class::MOP to C PMCs, I would be happy to
help port smop to C PMCs.
Kevin
Allison Randal wrote:
I spent yesterday pair programming with Sam Vilain on a prototype
object model written in PIR. We actually wrote two prototypes. The
first one had 2 levels of meta objects and the system was getting
pretty convoluted, so we scrapped it and started over.
I just checked in the second prototype to compilers/smop (Simple Meta
Object Protocol). The prototype has two classes, Class.pir, and
Attribute.pir. The instance of Class.pir is a class object, and the
instance of a class object is an object.
.local pmc class, init_args, myobj
init_args = new Hash
init_args['name'] = 'MyClass'
class = new 'Class', init_args
class.add_attribute('myattribute')
myobj = class.'new'( 'myattribute' => "Foo" )
The prototype code bootstraps off the existing object model, so for
now you create a class object with "new 'Class'". Ultimately this will
be the newclass opcode instead:
# class = newclass 'MyClass'
An Attribute is a simple datatype that stores the attribute name, its
type (if any), and a link back to the class that contains the
attribute. (It's the class's pattern for the attribute, not the
storage for the attribute value.)
This is a simple object model, but it can be used to implement as many
meta-levels as a particular HLL needs. Each level of class object is
just an instance of the next higher level of meta class object.
To move past bootstrapping on the current object model, the next step
is to implement this prototype at the C PMC level, and incorporate
much of the functionality of src/objects.c.
Allison
