typed lambda-calculus

theory (TLC) A variety of lambda-calculus in which every

term is labelled with a type.

A function application (A B) is only synctactically valid if

A has type s --@# t, where the type of B is s (or an instance

or s in a polymorphic language) and t is any type.

If the types allowed for terms are restricted, e.g. to

Hindley-Milner types then no term may be applied to itself,

thus avoiding one kind of non-terminating evaluation.

Most functional programming languages, e.g. Haskell, ML,

are closely based on variants of the typed lambda-calculus.

(1995-03-25)