In computer science, a quaject is an object-like data structure containing both data and code (or pointers to code), exposed as an interface in the form of callentries, and can accept a list of callentries to other quajects for callbacks and callouts.
They were developed by Alexia Massalin in 1989 for the Synthesis kernel,[1] and named for the Qua!
The origin of the term 'qua' is unclear; Massalin claims humorously that it is a sound made by koalas.
While the original Synthesis kernel required quajects to be written in hand-developed assembly language, this was done to avoid developing a complex compiler; Massalin noted that just-in-time compilation (JIT) for a high-level programming language that permits runtime code generation, as in Lisp or Smalltalk, can also apply this approach, though she also asserted that the complexity of such a compiler was likely to be prohibitive.
While shared methods can be accessed through a common table of pointers, individual quajects can also have methods that are generated specifically to tailor the performance for that quaject's behavior.