Η χρονική ανάδραση ή χρονική ενφώλευση (temporal recursion) είναι ένα εργαλείο για έλεγχο του κώδικα σε πραγματικό χρόνο κατα τη διάρκεια του προγραμματισμού 1. Την ιστοριά μας την εξιστορεί ο Sorensen παρακάτω:
So temporal recursion was born in early 2005, at least for me. Of course the idea was so obvious that others must be using the same technique, right? So I began trawling the archives. At which point I began to realise that the technique was far from common, indeed I struggled to find any references at all. After a lot of searching I discovered that Roger Dannenberg had used a similar technique in his CMU MIDI toolkit from the early 1990's, and in turn that he had borrowed the idea from Douglas Collinge's extremely interesting "Moxie" language (early 1980's). Neither Dannenberg nor Collinge used the term "temporal recursion" but the concept, albeit in a simplified form, was definitely there. James McCartney also made use of temporal recursion in his SuperCollider language from around 1996. Generally though the use of Temporal Recursion in practice, and in theory, appears to be quite rare.
Extempore supports both asynchronous cooperative concurrency and synchronous preemptive concurrency.