Classdef

From Octave
Jump to navigation Jump to search
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.

This page is a stub. We should begin documenting what classdef is implemented and what is not.

Not Supported

  • enumeration

See #44582 and help implementing it.


  • build-in class as superclass
classdef nonsense < uint32

end

See #44035

Example:

classdef MyClass < handle
end

c = MyClass();
cc = [c, c];   % won't work

For now you can use a cell-array of objects instead:

cc = {c, c};   % ok

Also see #44665

Example:

classdef MyClass < handle
    properties (SetAccess = immutable)
        x
    end
    methods
        function obj = MyClass()
            x = rand();
        end
    end
end

Use "private" properties as workaround.


  • Function handles to package methods and static class methods.

For example if we have +mypackage/myfunc.m, creating a function handle as fh = @mypackage.myfunc won't work. As a workaround, we can create an indirection using an anonymous function fh = @(varargin) mypackage.myfunc(varargin{:}). Similarly for static class methods where fh = @MyClass.myfunc isn't yet supported. Another workaround for package function handles is to use str2func, e.g. fh = str2func ("mypackage.myfunc").

A fuller example is also given below:

classdef method_function_handle_test

%  properties
%  
%  
%  end
  
  properties (Hidden, SetAccess = protected)
    hfoo = [];% handle to function
  end
  
  methods
  
    function self = method_function_handle_test ()
      self.hfoo = @foo;    
    end
    
    function bar (self)
        self.hfoo (self); 
    end

  end
  
  methods (Hidden, Access = protected)
    function foo (self)
      disp ('hello!');
    end
  end

end

Then running:

>> x = method_function_handle_test
error: @foo: no function and no method found
error: called from
    method_function_handle_test at line 17 column 17
stopped in <****>/scratch/mfiles/octave_tests/method_function_handle_test.m at line 17
17:       self.hfoo = @foo;

See #45351

For example, the following code gives a syntax/parse error:

classdef MyClass
    methods
        function obj = MyClass()
            myfunc()
        end
    end
end

function myfunc()
    disp('myfunc')
end

See #41723.

  • debugging in classdef methods (and +package directory functions)

Breakpoints cannot currently be set in classdef methods from the gui, but only from the command line:

dbstop @aclass\amethod

See #45404

  • Saving/reading classdef objects to/from (.mat) file

Supported

  • methods
    • static
    • private
  • properties
    • SetAccess (public/private/protected)

Open Bug Reports

Issues with basic classdef functionality

  • 51659 Calling 'methods' on self causes syntax error
  • 48682 print_usage fails within classdef block
  • 49434 which returns "built-in function" for classdef m-file
  • 48041 classdef: `help myclass` messes up `help @myclass/method`
  • 43047 help() does not see classdef files
  • 42620 exist() does not use "class" argument
  • 53874 doc_cache_create doesnt handle classdef documentation
  • 52096 meta.class.fromName throws error when class name not found.
  • 51377 Parse error for abstract methods
  • 44665 error in concatenation of classdef objects
  • 44582 classdef: missing support for enumeration
  • 48693 classdef subsref method is not called with correct nargout value

Classdef and +package directories

  • 54941 interpreter cannot find methods in files of classdefs in packages

Arrays of classdef objects

  • 53906 Cannot make an object array with square brackets
  • 47755 Access to object arrays
  • 47241 classdef: assigning property of handle object in object array constructs new object

I/O issues

  • 45833 support load/save of classdef objects

Debugger

  • 46451 unable to set breakpoints within classdef classes
  • 45404 Breakpoints cannot be set in classdef methods or +package function files

Lower-priority issues

  • 55488 Invalid use of colon char as classdef function's argument when subsref is overwritten
  • 55487 ismethod of custom classdefs always returning false
  • 54966 Error when assigning array to an object implementing subsasgn() subscripted using "{}"
  • 54783 subsasgn call when the subscripted expression contains the end keyword
  • 54028 copy of non-handle class instance is not deep
  • 53811 cellfun does not find overloaded function with function name argument
  • 52989 classdef: missing error messages on multiply defined properties
  • 52614 setting properties of classdef object during construction with inheritance
  • 52582 Dependent constant properties in classdef errors: no such file
  • 52123 Indirect memory leak in cdef_manager::initialize ()
  • 51285 max_recursion_depth error in classdef constructor
  • 50395 subclassing a class that is also defined as a variable fails
  • 50011 failure to report error on conflicting methods for classdef
  • 49379 classdef constructor: .argn. loses first argument, inputname(n) returns inputname(n+1)
  • 46652 whos bytes property not right for classdef classes
  • 45893 classdef properties are not reloaded when file is updated
  • 44934 classdef parser prints extra newline when failing to parse bad classdef file
  • 44643 classdef handle object can go into an recursive loop with isequal(obj1,obj2) if both are self-referential
  • 44035 classdef is unable to to subclass double

Documentation

  • 50729 Improve OOP documentation
  • 47908 Octave:classdef-to-struct not documented in warning_ids.m
  • 44590 More documentation for the current status of classdef implementation

Classdef examples in the wild