Resumen

Although functions are arguably the most important concept in mathematics, functions are not generally available as (first-class) values in all programming languages. The exception are, of course, the languages that derive their collective name from functions: the functional languages. After a short introduction to functional languages, this article concentrates on higher-order functions: functions that take other functions as arguments or return functions as results. This possibility allows for a number of fascinating applications, ranging from useful to esoteric.