Therefore, class delete methods must be able to work with partially constructed objects.įor example, the PartialObject class delete method determines if the Data property is empty before accessing the data this property contains. Support Destruction of Partially Constructed ObjectsĮrrors that occur while constructing an object can result in a call to delete before the object is fully created. For example, if a subclass uses an inherited abstract property to store an object handle, then the subclass should destroy this object in its delete method, but the superclass should not access that property in its delete method. If a superclass expects a property to be managed by subclasses, then the superclass should not access that property in its delete method. That is, MATLAB invokes subclass delete methods before superclass delete methods. MATLAB calls delete methods in the inverse of the construction order. The isvalid method returns false for the handle object within the delete method because object destruction begins when the method is called. After the delete method finishes execution, handles to the deleted object in any variables in any workspace are invalid. If a delete method creates new variables that contain a handle to the object being deleted, those handles are invalid. MATLAB does not destroy these properties until after the delete methods for the class of the object and all superclasses finish executing. Once called, a delete method cannot abort or prevent object destruction.Ī delete method can access properties of the object being deleted. The object is destroyed when the call to delete is made explicitly in MATLAB code or when called by MATLAB because an object is no longer reachable from any workspace. Handle Object During delete Method ExecutionĬalling the delete method on an object always results in the destruction of the object. This design enables delete to work on object arrays containing a mix of valid and invalid objects. Therefore, a delete method is passed only one scalar argument with each invocation.Ĭalling delete on a deleted handle should not error and can take no action. MATLAB calls the delete method separately for each element in an array. end end delete Called Element-Wise on Array The function that is passed to the function-function is usually referred to as passed function.% obj is always scalar. For example, > fset = fset(1,1) % get the area of an ellipse with semi-axes (1,1).įunction-functions are functions that operate on other functions that are passed to it as input arguments. You can also create an array of function handles by collecting them into a cell or structure array. For example, to calculate the integral of $f(x)=x^2$, as implemented in getSq() above, on the range $$ define, > f = q = integral(f,0,1) If you don’t add () at the time of call, then simply another function handle will be created, now assigned to a, > h = a = hįunction handles can be passed as variables to other functions. If the function does not require any inputs, then you can call the function with empty parentheses. Then you can create a function handle on MATLAB command line like the following, > f = a = 4 For example, if you have a function called myfunc, you can create a handle named f for it as follows, f = example, function out = getSq(x) The general method for creating a function handle is to precede the function name with an sign. You can see if a variable, say h, is a function handle using isa(h,'function_handle'). Call local functions from outside the main function. ![]() ![]()
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