Re: OOP and load/save

[Judd Storrs]

Sorry about the previous message, I accidentally tried emacs line edits in gmail and sent the message ;) 

I was playing around in Matlab R2007b and found something that may shed some light on what Matlab is doing. If I create 

@Foo/Foo.m
function f = Foo()
  f.dataelement = 'I am Foo';
  f = class(f,'Foo');

Then in matlab 

>> bar = Foo() ;
>> save test.m bar
>> exit

Next edit break @Foo/Foo.m

function f = Foo()
  f = [];

Then restart matlab

>> load test.mat
Warning: Could not determine the fields for class Foo by calling the
         constructor with no input arguments.  The object bar has been
         converted to a structure.  To eliminate the conversion create
         an object of class Foo before calling LOAD.


So, I think Matlab keeps an internal memory of each class structure. Probably the first time a class of a specific type is created, Matlab remembers the member information. If Matlab doesn't have member information it calls the constructor with no arguments. I'll do some more testing to verify.

--judd