Development

The significance of functional programming is revealed as that the feasible approach to language extensibility which it enables is further applicable to programming in general and beyond. The essence of functional programming is its enablement of programmer-defined function-valued functions. The feasibility of language extension by normal programmers depends upon the exclusion of interpretation in favour of direct definition, and higher-order functional programming is the key to enabling definitional rather than interpretational extensions. Functional programming thus offers the opportunity for the exclusion of the interpretation that otherwise pervades programming in general, and may be applicable beyond to analog computing and systems in general. Nevertheless, specific technical challenges need to be met before “totally functional programming” can realise its promises