On the Evolution of Unnatural Language

A search of the web reveals that natural language is considered to be language which a human would consider natural and unnatural language is language a human would consider artificial. This clearly raises interpretation questions and plenty of leeway so I am going to take the latter view here and bend it somewhat to consider programming languages as particularly good examples of unnatural language. Programming languages are something like 60 years old. Their evolution tells us much about the triumph of creativity over parsimony; the need for diversity and the frequent triumph of politics over common sense or logic. Yet their minimum set of features is defined by the beauty and simplicity of the Böhm-Jacopini theorem [1] and their underlying similarity in information theoretic terms is shown in the theorem proved by myself in [3], [4]. This essay is a reflection on programming languages both old and new, engineering, systems evolution and the role of education. 1 A Little Essential Background In 1966, two Italian computer scientists Corrado Böhm and Guiseppe Jacopini proved a very important and relatively unsung theorem which essentially demonstrated that every computable function could be implemented in a programming language which contained three control structures which we recognise today as sequence, selection and iteration [1]. This seminal paper also initiated the structured programming debate, however from our point of view it sets the minimum a programming language requires to implement every computable function. Such minimum implementations would be a bit bleak to use in practice so it is interesting therefore to consider how much else computer scientists feel they must add to enhance “expressive ability”.