Editing Persistent data structure (section)

=== Prolog ===
Prolog terms are naturally immutable and therefore data structures are typically persistent data structures. Their performance depends on sharing and garbage collection offered by the Prolog system.<ref>{{Citation|title= The Implementation of Prolog - Patrice Boizumault|date=1993|isbn=9780691637709|url=https://press.princeton.edu/books/hardcover/9780691637709/the-implementation-of-prolog|last1=Djamboulian|first1=Ara M.|last2=Boizumault|first2=Patrice|publisher=Princeton University Press }}</ref> Extensions to non-ground Prolog terms are not always feasible because of search space explosion. Delayed goals might mitigate the problem.

Some Prolog systems nevertheless do provide destructive operations like setarg/3, which might come in different flavors, with/without copying and with/without backtracking of the state change. There are cases where setarg/3 is used to the good of providing a new declarative layer, like a constraint solver.<ref>{{Citation|title=The Use of Mercury for the Implementation of a Finite Domain Solver - Henk Vandecasteele, Bart Demoen, Joachim Van Der Auwera|date=1999|url=https://lirias.kuleuven.be/retrieve/440562}}</ref>