Manipulating an anonymous function

I have a handle class myClass which has a property myFunc that is a function handle which I define with an anonymous function, e.g.

myClass.myFunc = @(x) 2*x

Is it possible to use myFunc to redefine itself? I tried

myClass.myFunc = @(x) -myClass.myFunc(x)

but trying to evaluate this led to a max recursion error. My function is defined inside of a class method using a local variable like:

myClass.myFunc = @(x) localVar*x

Otherwise, I would consider using func2str, but that doesn't help because it produces the expression involving localVar which is no longer defined. Right now, I am using

myClass.myOtherFunc = @(x) -myClass.myFunc(x)

but I'd prefer not to have to create a separate property just for this.

Answer 1

[Walter Roberson]

tmp = myClass.myFunc;
myClass.myFunc = @(x) ~tmp(x);

[Will]

I get "Undefined function 'not' for input arguments of type 'function_handle'." (and the same thing but with "uminus" instead of "not" if I switch the ~ with -).

[Walter Roberson]

Are you sure you have the (x) after tmp ? Could you show the exact two lines of code that you use?

[Will]

Sorry, your solution works for me now. I tried it before and got the error I mentioned, but maybe I had a typo somewhere.

Answer 2

[per isakson]

I don't understand what you want to achieve, but

    >> myc = my_class();
    >> x = myc.foo(5);
    >> x
    x =
       -10

where

    classdef  my_class 
        properties  
            foo1
        end
        methods
            function    this = my_class( ) 
                this.foo1 = @(x) 2*x;
                this.foo1 = @(x) -this.foo1(x);
            end
            function    out = foo( this, val )
                out     = this.foo1(val);
            end
        end
    end

[Will]

That is basically what I was trying to do. If you change the first line of your class definition from

    classdef my_class

to

    classdef my_class < handle

you will get a max recursion error when you run myc.foo(5).

[per isakson]

My mistake. However, this looks like a bug to me. Did you report to tech-support?