MATLAB: How to get implicit conversion between strings and function handles when using in-line property validation in a MATLAB class

MATLABmethodsooppropertysetsettervalidation

I have defined the MATLAB class 'simpleClass' as shown below:
classdef simpleClass
    properties
        prop1 function_handle
    end
end
When I create an instance of this class and try to assign a 'char' to 'prop1', as shown below, an error is thrown despite the fact that strings that are function names are convertible to function handles.
>> a = simpleClass
>> a.prop1 = 'sin'
Error setting property 'prop1' of class 'exampleClass':
Invalid data type. Value must be function_handle or be convertible to function_handle.
However, the conversion below returns a valid function handle:
>> str2func('sin')
ans = 
     function_handle with value:
        @sin
Why is an error thrown when I try to set 'prop1' using a string?

Best Answer

Unfortunately, implicit conversion between 'char' arrays and function handles is not currently supported for inline property validation.
As a workaround, you can declare a setter method for 'prop1' that explicitly performs the type checking and conversion desired. The example below illustrates how to do this:
classdef simpleClass
    properties
        prop1
    end
      methods
          function obj = set.prop1(obj,arg)
               if ischar(arg)
                  obj.prop1 = str2func(arg);
              elseif isa(arg,'function_handle')
                  obj.prop1 = arg;
              else
                  error('Unaccepted datatype')
              end
          end
      end
  end
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