Thanks Pantxo, I will open a new bug report about the remaining small issue.

@gyom: I agree with comment #10.  Please open a new bug report about how open() should respond when there is an error condition.

The error might be because the file doesn't exist, or because there is no known handler.

It would be useful if we knew how Matlab handled errors.  For example

open ('FooBar')         % non-existent file, no output
x = open ('FooBar')     % output requested

@pantxo:

1. I think what surprised me is that if I double-click on a binary file not recognized by the system (e.g. a binary file for which 'file' says 'data'), then nothing happens. A warning could be displayed in that instance.
2. Sounds good!

@pantxo: I applied your patch and it seems to work fine, thanks!
I've got two comments:
1/ When a file extension is not recognized, Matlab defaults to open the file in its text editor while Octave does nothing. If you have a file named file.blah, Matlab opens it in its text editor while Octave will open the default text editor for the system.
2/ If .ofig is hardcoded in open.m, it means there will not be a function openofig.m with the extra optional inputs ("new", "reuse", "visible", "invisible" ) that openfig.m has. What about hardcoding open.m to use openfig.m for .ofig files and have all of the options there (for both .fig and .ofig)?

Thank you for your quick implementation pantxo!

To answer your question: Yes, Matlab allows overriding built in open functions.

This solution would be preferable in my opinion. It would allow a free configuration for various file types.
 
Therefore it would be nice if a central "openAny.m" octave function would be called that could be used to handle the file recognition.

function result=openAny(filename)
  FileType = File_Type_Recognition_Function(filename)
  switch(FileType)
  case '.ofig':
    result=openOFIG(filename);
  case '.otherfiletype':
    result=openOTHERFILETYPE(filename);
    .
    .
    .
  otherwise:
    error('Filetype of "%s" can not be loaded!');
  endswitch
endfunction

This kind of interface is limited to load functions returning a single argument. Therefore using varargout as for results may be more suitable.

Hi,

>> So .mat files could be restored with "load()" ...

This is already the case: double clicking on a data file will load variables in the base workspace

>> ... and saved figures with hgload()

Since .ofig files are data files, the structure they contain is also loaded as a variable in the base workspace, but it would be easy to implement this. The function to modify is files_dock_widget::display_directory (in files-dock-widget.cc).