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

[Patrick Häcker]

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

                 Summary: Inheritance and anonymous functions do not work
together
                 Project: GNU Octave
            Submitted by: magicmuscleman
            Submitted on: Do 31 Mär 2011 11:12:54 GMT
                Category: Interpreter
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Crash
                  Status: None
             Assigned to: None
         Originator Name: Debian 6.0
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.4.0
        Operating System: GNU/Linux

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Details:

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.



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File Attachments:


-------------------------------------------------------
Date: Do 31 Mär 2011 11:12:54 GMT  Name: testInheritance.tar  Size: 6kB   By:
magicmuscleman

<http://savannah.gnu.org/bugs/download.php?file_id=23063>

    _______________________________________________________

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