Inner Method Dispatch for Python
Pyta = Python + Beta
Inner dispatch is used to guarantee pre- and post-conditions without using auxiliary methods. An external dispatch results in the lowest method that calls inner being called. An inner(cls, self) call calls the next highest method that has an inner call, or the highest method if there is no higher inner method. super works the same as before, but take care not to cause an infinite loop.
from pyta import inner, BetaMetaclass class A(object): def foo(self): print "world!" class B(A): # Can inherit from regular classes # The lowest class in the hierarchy that uses `inner` needs the metaclass __metaclass__ = BetaMetaclass def foo(self): inner(B, self).foo() # Calls C.foo super(B, self).foo() # Calls A.foo class C(B): def foo(self): print "Hello, " obj = C() obj.foo() # External dispatch; calls B.foo
Because using inner in a superclass completely changes which method an external dispatch resolves to (it’s no longer the most-overriding method) the metaclass is required to inspect the source of the methods and sprinkle some magic to make it all work.
In order for everything to work properly, you must call inner(cls, self) lexically. In other words, it won’t work if you do this:
bar = inner bar(cls, self).foo()
from pyta import inner as bar bar(cls, self).foo()
Currently, the implementation doesn’t distinguish between strings vs. actual method calls, so if your method contains a string like "text inner( moretext", it’ll break everything.