Issue 4968: Clarify inspect.is method docs (original) (raw)

inspect module in 3.0

.isclass: says "Return true if the object is a class." Since the issue of builtin versus Python coded is involved in all the other methods below, I would expand this to "Return true if the object is a class, whether built-in or Python-coded." to emphasize that this is not an issue for this one.

.isfunction: current "Return true if the object is a Python function or unnamed (lambda) function." falsely implies that there is such a thing as 'unnamed (lambda) function; different from 'Python function'. By test, it just returns True for 'function' objects. Suggestion:

"Return true for Python-coded functions, including unbound Python-coded methods." or possibly "Return true for functions created by def statements and lambda expressions, including unbound Python-coded methods.

.ismethod: "Return true if the object is a method." should be specified to something like "Return true if the object is a bound method written in Python."

.isbuiltin: says "Return true if the object is a built-in function." but actually tests for membership in class 'builtin_function_or_method'. I believe that truth is "Return true if the object is a built-in function (but not a class) or a bound built-in non-special method." It is True, for instance, for [].append but not [].hash. I am assuming that this behavior is intended and not a bug.

.ismethoddescriptor: "Return true if the object is a method descriptor, but not if ismethod() or isclass() or isfunction() are true." begs the question of what a method descriptor is. I believe the following is both true and clearer. "Return true if the object is a built-in method and isbuiltin() is false.

I would follow with "The methods isclass, isfunction, ismethod, isbuiltin, and ismethoddescriptor are mutually exclusive." I believe the following is true, and could be added also. "Exact one is true for any instance of a built-in callable class."