To the (now background)-thread of an (alternative) language for programming 'sp's I forgot to mention javascript. I believe both the licenses for the Mozilla and the Google/Chromium javascript engines would allow for porting to MariaDB. Some extensions would probably be necessary to support database objects/functionalities. But actually I think that javascript is the best option for a cross-platform implementation (even though it does not look 'ADA-style´'). And it would provide arrays and more programming options for 'sp's.
Buti t would not be trivial to implement, of course.
-- Peter