Tham khảo tài liệu ' a guide to matlab object oriented programming episode 2 part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 314 A Guide to MATLAB Object-Oriented Programming environment pass-by-reference syntax can reduce code quality and interfere with debugging. If you press me I recommend that you use pass-by-reference very sparingly. Even so if you decide to include pass-by-reference syntax it s important to have a good strategy. In the examples that follow we will implement one possible strategy. Currently all functions in the shape hierarchy use standard pass-by-value syntax. Consequently all mutators must return a copy of the modified object and a user must assign the returned object to a variable. This works well whenever it is obvious that a function is a mutator. For some functions it is difficult to decide at a glance whether the function is a mutator. In the shape hierarchy draw is a mutator but this fact is easy to forget. Calling draw modifies mFigureHandle but mFig-ureHandle is an internal implementation detail. Clients should be shielded from internal details and pass-by-reference is another tool that can be used to help enforce the separation between public and private. The current implementation of draw includes the following test if nargout 1 warning draw must be called using obj draw obj else Since all side effects from draw are private a client might reasonably expect to call draw without assigning the return value. In the current implementation that would result in an error. The client doesn t get the desired result but at least the error message tells what to do. With pass-by-reference emulation draw might still perform a nargout test however the result of the test would no longer throw an error. Instead pass-by-reference emulation would be used to modify the input object in place. The change would be immediately reflected in the client s workspace. In the examples that follow we will modify draw by allowing it to be called as a mutator or with pass-by-reference syntax. Like member functions public member variables can include pass-by-reference capability. This .
