The Evolution of Concepts and Languages of Computing

Digital computers are opening exciting new possibilities for progress in language translation, information retrieval, psychological modeling, problem solving and theorem proving. These have resulted not because of the microsecond arithmetic speed but because of the ability to manipulate symbols: to read, write, store, compare, and replace symbols and to follow different courses of action according to differences between symbols. Thus, language in a general sense is a common aspect of these new applications. Programmers have been extending the usefulness of computers through the evolutionary development of most artfully conceived languages. Recently, mathematicians and logicians have been proving theorems about formal languages, while linguists have been discovering laws that humans instinctively observe whenever they use natural language. Fruitful cross pollination among such endeavors now promises greatly accelerated progress in determining whether symbol manipulation is for information processing applications what numerical analysis is for arithmetic applications. This paper first reviews the evolution of programming languages from the early days when all programming was done in machine languages, through symbolic coding systems, interpreters, assemblers, generators, and compilers, to the recently developed list processing languages. Then the applications of these languages to game playing, problem solving, theorem proving, and behavior and biological modeling have been described briefly. Finally, in anticipation of extending the capability of computers to accept, use and generate natural languages, the paper concludes with an introduction to some of the contemporary work on formal language theory, including a discussion of six families of abstract languages and their practical implementation.