In computer science, a function type (also arrow type or exponential) is the type of a variable or parameter to which a function has or can be assigned or the result type of a higher-order function returning a function.
A function type depends on the type of the parameters and the result type of the function (it, or more accurately the unapplied type constructor · → ·, is a higher-kinded type). In theoretical settings and languages where functions are defined in curried form, such as the simply typed lambda calculus, a function type depends on exactly two types, the domain A and the range B. Here a function type is often denoted A → B, following mathematical convention, or BA, based on the fact that there exist exactly BA (exponentially many) set-theoretic functions mapping A to B.
Read more about Function Type: Programming Languages, Denotational Semantics
Famous quotes containing the words function and/or type:
“Nobody seriously questions the principle that it is the function of mass culture to maintain public morale, and certainly nobody in the mass audience objects to having his morale maintained.”
—Robert Warshow (1917–1955)
“Are God and Nature then at strife,
That Nature lends such evil dreams?
So careful of the type she seems,
So careless of the single life;”
—Alfred Tennyson (1809–1892)