[3] The FP language was introduced in Backus's 1977 Turing Award paper, "Can Programming Be Liberated from the von Neumann Style?
The paper sparked interest in functional programming research,[4] eventually leading to modern functional languages, which are largely founded on the lambda calculus paradigm, and not the function-level paradigm Backus had hoped.
These, plus simple definitions, are the only means of building new functions from existing ones; they use no variables or substitutions rules, and they become the operations of an associated algebra of programs.
[5] In the 1980s Backus created a successor language, FL as an internal project at IBM Research.
Unlike FFP, another one of Backus' own variations on FP, FP84 makes a clear distinction between objects and functions: i.e., the latter are no longer represented by sequences of the former.