Improve performance of isfield from linear time to constant time (bug #58105) Patch author: Anonymous in Bug #58105 Comment #7 https://savannah.gnu.org/bugs/index.php?58105#comment7 The isfield function was taking time proportional to the number of fields in a struct to determine whether something was a member or not. With this change, isfield performance becomes constant irrespective of the number of fields, speeding up performance by over 200X, and also allowing the use of struct as a hashmap if the user desires. ov-base.h: Add new isfield function declaration ov-base.cc: Add new isfield function definition ov-struct.h: Add new isfield function definitions ov-struct.cc: Do not call map_value ov.h: Add new isfield function definition

Things to do before making a release:

  * Update the version number and release date in configure.ac.

  * Update the OCTAVE_API_VERSION number in configure.ac.

  * Update version number and release year in CITATION.

  * Update the etc/NEWS.N.md file corresponding to the major release
    number N.  Include release date in Summary header.

  * Update the NEWS-<VERSION>.html, index.in, news.in, and download.in
    files for the web site.

  * Copy tarballs to ftp.gnu.org.

  * Post a release announcement to the help@octave.org and
    info-gnu@gnu.org lists.

  * Update https://wiki.octave.org/Release_History page.