In Pharo, the method you're looking for is ClassDescription>>allMethodsInCategory:
:
| selectors |
selectors := MyClass allMethodsInCategory: #'protocol name'.
To find methods in a class-side protocol, just send to the metaclass instead:
selectors := MyClass class allMethodsInCategory: #'protocol name'.
Another solution you might want to consider, though, is to use a pragma to mark your methods instead. See the comment on the Pragma
class for details of that approach. It has the advantages that other packages can freely add methods belonging to your group (which need to be in a * protocol), and that the pragma can be used to store other metadata as well (such as an evaluation order, for example).
NB. The selector allMethodsInCategory:
has been deprecated in Pharo 3.0 and later in favor of allSelectorsInProtocol: