Online Developer Meeting (2021-08-24)

• Date: Tuesday, August 24, 2021 @ 18:00 UTC
• Location: https://meet.jit.si/octave-dev-2021-08-24

Todays topics

• Meet and greet 5 minutes before meeting (audio testing).

Switch this meeting to more casual format

• In the future notes of the talks will be added to this wiki in a more sparse fashion.

liboctave

• Make more use of STL
• Not all liboctave components can be replaced by STL containers, as the ND-indexing is not supported.
• string_vector class probably replaceable by STL containers.

Tips for Octave C++ code writers

Such as packages, toolboxes, etc.

• Prefer OCTAVE_LOCAL_BUFFER over heavy-weight Array object to store results of (Fortran-) library calls.
• Prefer octave_value type variables over internal data structures.
  • Examples: Function handle class and Range class.

For package maintainers

• Do not use error_state anymore! https://octave.discourse.group/t/eliminating-use-of-error-state-in-octave-code/1515
• Do not suppress compiler warnings about deprecated features today, those are the bug reports of tomorrow, when it is too late.

octave namespace

• jwe made many breaking changes on the default branch moving symbols in the octave namespace, to keep the namespaces tidy.

Deprecations

• The operators .+, .-, and ** https://octave.discourse.group/t/deprecating-fortran-style-exponent-operator/1516 will be deprecated.

Trolling

• In case of trolling behavior of users, please mark the thread, thus a Discourse admin can close the threat and mute the user.
  • DO NOT FEED THE TROLL: Any further answer or conversation is most likely a waste of emotions and time.
• Any user violating the usage conditions https://octave.discourse.group/tos#heading--conditions will be muted or removed from the forum entirely.

Code sprints

• Wish for more code sprints, e.g.,
  • "m_" convention https://octave.discourse.group/t/using-m-prefix-for-member-variables-in-c-classes/1517/17
  • Close easy closable bugs Short_projects#Easy_Closes

Previous topics

The following items were not discussed. Just some links to progress on those items are displayed.

Octave 6.3 released

• No "official" announcement happened. Maybe reuse abandoned mailing-lists to announce important events, such as releases.
• How do distribution maintainers get to know about Octave releases?
  • Contact Debian maintainers of the Octave package to maybe improve our communication.
    • Done, already answered: https://lists.gnu.org/archive/html/octave-maintainers/2021-07/msg00001.html

Octave 6.4 / 7 / 8

• Discussion how to continue with the development.
  • jwe wants to introduce breaking changes (see below).
• Octave should stick with the ~yearly major release cycle
  • Probably no Octave 6.4 (only if severe bugs occur).
  • Octave 7 (default branch)
    • Should no longer receive "very" breaking changes (e.g. String-class for Octave 8)
    • Has about 305 bugs fixed (not 100% reliable figure) and should not wait another year until many bigger outstanding changes happen (will be deferred to Octave 8)
    • Tentative plan:
      • November 2021 merge default to stable.
      • End of 2021 release of Octave 7
  • Octave 8 (new default branch)
    • No clear decision how to handle very breaking changes until November 2021 merge default to stable. Depends on future needs.

Octave 7 / 8

• Function argument parsing (introduced in Matlab R2019b, rather new)
  • jwe will continue to work on this feature on Octave 7 (default branch)
  • If feature cannot be completed by the end of the year, it will be disabled on parser-level (error), and introduced in Octave 8 one year later.
• New GUI command widget
  • Possible to introduce it as user opt-in in Octave 7
  • Pending issues:
    • Command-widget does not look like the previous one (textbox for command input)
    • jwe needs better looking widget (avoid developing a new one)
    • No possibility to run external applications (like emacs, pager), which is already partially broken now. Need to implement own paging strategy (scroll bars, etc.)
• Deprecation of Octave operators
  • Improve Matlab compatibility
  • Some extensions make it painful to implement Matlab compatible command-style function calls? See also the discussion about this topic.
    • Remove rarely used extensions like "**" power.
    • Discussion about removal of "+=", "++", etc. No final decision made.
    • Often used extensions must probably stay (like "!" or "!=" used in place of "~" or "~=").

C++ shared pointer / liboctave

• jwe had a look at Octave own reference counting
• Wish to replace it with C++ shared pointers
• Expert knowledge wanted! jwe opened a discussion thread
• jwe identified "copy expensive" inefficiency about mxArray to octave_value conversion? Root of the trouble lies in historical handling of complex data? See this discussion.

See also

• Next meeting: Online Developer Meeting (2021-09-28)
• Last meeting: Online Developer Meeting (2021-07-27)