I know it'a s long while, but we finally made release of Preg 2.6 (and Regex Constructor block) which can work well for Moodle 2.6 and basically workable in 2.7. too (strict standarts editing problems should be fixed in release).
Since it involve a number of plugins with various stability rate I do not place it in Moodle plugins database for now to not harm users using automatic upgrading feature. You can download it there - https://dl.dropboxusercontent.com/u/51745292/preg_26_beta.zip - a full archive that should be unpacked in Moodle root folder (the one with config.php).
I hope new features will compensate you for the wait:
- panning and zooming Syntax Tree and Explaining Graph - Dmitry Pahomov;
- collapsing mode in the Syntax Tree - Grigory Terekhov;
- rectangle selection mode in Explaining Graph (so you can select part of the graph and see corresponding parts of regex) - Vladimir Ivanov;
- Explaining Graph now case show all complex regex operators like conditional subpatterns - Vladimir Ivanov;
- formal languages block (used by next word hint) now have user interface and you can choose language visibility on the course level (so programming course may see only C++ language creating their questions, while other courses may see only English ones) - Dmitry Mamontov.
Please write me for any problems found with this code. If all is OK, release will be made in a week.