structs de/serialization(e.g. JSON) and complex initialization/modification routines at runtime that rely on these structs/objects, data-oriented architecture a

structs de/serialization(e.g. JSON) and complex initialization/modification routines at runtime that rely on these structs/objects, data-oriented architecture and internal script interpreters at some level. Lisp itself can embedded in C, but at that point the program likely has a more efficient scripting DSL at place.