The Personal Web Pages of Chris X. Edwards Regular Expression Tutorial

HISTORY OF REGULAR EXPRESSIONS

One might assume that regular expressions were a diabolical invention of early Unix programmers intent on preserving their own job security by introducing yet another complexifying tool. It turns out that the study of regular expressions actually goes back to the 1940's when scientists studying neurophysiology were trying to model neuron functions. Over time, these models were mathmatically formalized into a conceptual system called "regular sets". The notation for expressing these regular sets was called "regular expressions". This kind of notation represents a specialized yet complete communication system. In the Chomsky hierarchy of grammar classification, regular expressions fall into the category of languages that are most rigidly defined. This means that unlike natural languages such as English, regular expressions have absolutely no ambiguity. There is absolutely no dependency on context. In other words, regular expressions follow the same rules in the same way every time no matter what that data is. Presumably this is the way that neurons are thought to behave.