Forward Indexing Operations - MATLAB & Simulink (original) (raw)

Main Content

The three mixin classes that enable customizing indexing operations—matlab.mixin.indexing.RedefinesParen, matlab.mixin.indexing.RedefinesDot, and matlab.mixin.indexing.RedefinesBrace—work independently. You can implement all three indexing operations, but you also have the option of just implementing one or two of them. You can also choose to customize just one or two levels of indexing and forward additional operations to another MATLAB® object.

For example, this expression shows three levels of indexing:

You can choose to customize only the parentheses indexing by inheriting fromRedefinesParen and then forward the remaining indexing operations (dot and brace) to the default behaviors. This class fragment inherits fromRedefinesParen:

classdef MyClass < matlab.mixin.indexing.RedefinesParen

properties (Access = private) prop end

methods (Access = protected) function varargout = parenReference(A,indexOp) idx = indexop(1).Indices;

     % Handle customized parentheses indexing
     temp = A.prop(idx);

     % Forward remaining indexing to temp
     [varargout{1:nargout}] = temp.(indexOp(2:end));
  end

end end

The forwarding syntax is the dynamic dot indexing syntax with theIndexingOperation instance:

This expression handles all of the indexing operations after the first parentheses. In other words, the indexing expression described by indexOp(2:end) is forwarded to temp. In this example, indexOp(2) andindexOp(3) are the dot and brace indexing operations, respectively.temp.(indexOp(2:end)) translates to:

For customized dot indexing, the forwarding syntax maintains the access permissions from the original context of the main indexing expression. For example, after the parentheses indexing obj(1).prop{7} is handled, MATLAB handles the dot indexing, temp.prop{7}, using the same context that the initial indexing expression started with. When you callobj(1).prop{7} inside the class, the private propertyprop is accessible. When you call obj(1).prop{7} outside of the class, prop is not accessible.

Forward Indexing Operations - MATLAB & Simulink (original) (raw)

See Also

Topics