CODEWITHSUNDEEP
matlabooppropertiesinitialization
CitizenInsane
CitizenInsane

Reputation: 4855

Unexpected initial property value with Matlab oop

I have defined a simple class called MySettings, which internally holds for others settings defined in a class called MySubSettings:

%% --- Definition for MySubSettings
classdef MySubSettings < handle    
    properties
        Fifi = 666;        
    end    
end

%% --- Definition for MySettings
classdef MySettings < handle    
    properties
        Riri = 42; 
        Subs = MySubSettings();
    end   
end

The first time I instantiate MySettings with s = MySettings(); everything is ok (Property Riri is initialized to 42 and Subs is an instance of MySubSettings with property Fifi initialized to 666) ... So far so good ...

Now if I modify property values and reassign s to new instance like this:

s.Riri = 0;
s.Subs.Fifi = 0;
s = MySettings();

Then inspecting new values for properties in new s instance ... I have s.Riri which is equal to 42 (as expected) ... but s.Subs.Fifi is still equal to 0 where I would have expected it to be reinitialized to 666 (???)

Why only Riri is initialized ? Am I doing something wrong or is it a bug ?

Note: I have the issue with R2013b and R2014b.

Upvotes: 2

Views: 51

Answers (1)

CitizenInsane
CitizenInsane

Reputation: 4855

My misunderstanding ...

Values assigned to properties in class definition are not initial values (like in C# for instance) BUT default values and are no longer re-evaluated after the class is first used.

In my example, as MySubSettings is a handle class, any value assigned to it becomes the new default for next instances.

This default value concept is a bit confusing ... but ok, it was my mistake ... sorry.

Upvotes: 3

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