Regular expression
Expresión regular
- Date
- 1951 · confidence high
- Place
- Santa Monica, California, United States
- Credited to
- Stephen Cole Kleene (RAND Corporation)
- Field
- Knowledge & symbols
What was discovered
Kleene formalized 'regular events', an algebraic notation describing sets of sequences recognizable by finite automata, in a RAND Corporation research report. It is the mathematical basis of text pattern search and validation.
Ken Thompson implemented them practically in QED and later in the Unix ed editor (1968), popularizing them in computing.
What it led to
- Formal language and automata theory
- Text search tools (grep, editors, compilers)
- Data validation and lexical analysis in programming