[Octave-bug-tracker] [bug #32964] Inheritance and anonymous functions do not work together

[Patrick Häcker]

Follow-up Comment #1, bug #32964 (project octave):

I cannot see the full text of my previous entry in the browser, so I repost it
without using verbatim:

There is a problem in Octave with the combination of inherited objects and
the
usage of anonymous functions/methods, which works with Matlab. It's probably
best to give an example:

Assume there is a class "Parent":
Constructor:
function parent = Parent()
    parent = class(struct(), 'Parent');
end

Method:
function parentMethod(parent)
    disp(['This is a method of class Parent called with an object of class '
class(parent)]);
end


Assume there is another class "Child" which inherits from "Parent":
Constructor:
function child = Child()
    child = class(struct(), 'Child', Parent());
end


Now we want to test our two classes:

function testInheritance()
    % This works in Matlab and in Octave
    child = Child();
    parentMethod(child);

    % This works, too
    parent = Parent();
    fun = @() parentMethod(parent);
    fun();

    % This works in Matlab but not in Octave
    fun = @() parentMethod(child);
    fun();
end


The result of this test is:

This is a method of class Parent called with an object of class Child
This is a method of class Parent called with an object of class Parent
error: parentMethod: no method for class Child


So as you can see, the call of the parent method fails for inherited objects
when using an anonymous function. Thus it's not possible to use higher order
functions with inheritance in Octave. I attached the code as an tar file.

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  <http://savannah.gnu.org/bugs/?32964>

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