An algorithm which turns a term into a function of some variable. The result of using bracket abstraction on T with respect to variable v, written as [v]T, is a term containing no occurrences of v and denoting a function f such that f v = T. This defines the function f = (\ v . T). Using bracket abstraction and currying we can define a language without bound variables in which the only operation is monadic function application.

See combinator.