REGULAR EXPRESSIONS History

 

REGULAR EXPRESSIONS

 

Introduction

Regular expressions: are text patterns that define the form a text string should have.

 

 Regular expression History

Regular expression history goes back to 1943 when neurophysiologist

Warren McCulloch and Walter Pitts published logical calculus of the ideas immanent in nervous activity. This paper not only represented the beginning of the regular expression but also proposed the first mathematical model of neural network.

The next step in 1956  the mathematician Stephan Kleene wrote  the paper

Representation of events in nerve nets and finite automata. where he coined  the term regular sets and regular expressions.

In 1968 a legendary pioneer of computer science took Kleen’s work and extending by publishing his studies in the paper regular expression search algorithm. the engineer was Ken Thomson known for the design and his
implementation  of Unix , B programming language, UTF-8 encoding, and more .

He included it in version of QED , where u can search with a regular expression using the following syntax :

Then the release of the non-proprietary library of regex by Henry spence , and later the creation of the scripting language Perl  by Larry Wall  that pushed the regular expression to the mainstream , and added modifications to the original regular expression syntax creating Perl flavor then The IEEE thought their POSIX standard has tried to standardize and give better Unicode support to the regular expression syntax and behaviors. This is called the POSIX flavor of the regular expressions.

POSIX :  The Portable Operating System Interface is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating.

 

Today, the standard Python module for regular expressions—re—supports only Perl-style regular expressions. There is an effort to write a new regex module with better POSIX style support   . This new module is intended to replace Python's re module implementation eventually.