Re: Robustness against accidental shadowing of 'core' functions

[Andrew Janke]

On 9/5/18 9:14 AM, Tasos Papastylianou wrote:
>
> My own opinion is that functions that are relied upon for 'core'
> functionality (such as 'glob' seemingly being used internally by 'pkg')
> should be called in a more carefully robust way (i.e. via 'builtin'), to
> prevent accidental breakage of core functionality in the event that an
> external package manages to shadow that function for whatever reason
> (good or bad).
>
> [...]
>
> Thoughts?

Namespaces seem like a natural fit here, at least for some of the problem.

If you were designing Octave from scratch now, and wanted to make Matlab 
compatibility a priority, you could have an "octave" namespace that 
contained all the functions supplied by Octave that are not present in 
Matlab. That way you only have one global name that's subject to 
collision, and one that users are unlikely to use themselves. Similarly, 
functions for Octave's internal use that shouldn't be called by user 
code could go in "octave.internal". It would be "future-proof", too: you 
wouldn't have to worry about future versions of Matlab introducing a 
"glob()" function with incompatible semantics. Perhaps future 
Octave-specific global functions and classes should go in a namespace, 
to avoid this issue.

Matlab seems like it might be going this way, too, with a +matlab 
namespace hierarchy.

Seems like it would be a lot of work (and code uglification) to try to 
defend against this shadowing everywhere, though, with either namespaces 
or "builtin".


On 9/5/18 4:57 PM, Kai Torben Ohlhus wrote:

> Honestly, we are talking about a
> non-Matlab function "glob", thus it is not a Matlab compatibility issue
> if it is not working.

The user has a program that works under Matlab, but fails under Octave. 
That sounds to me like the definition of a Matlab compatibility issue. 
The space of global identifiers which are available for user functions 
without interfering with the system's functioning is part of the 
language/platform's behavior.

Cheers,
Andrew