TWO TYPES OF
TWO TYPES OF
REGEX ENGINES
REGEX ENGINES
. Text-directed
Thompson 1968, 400 LOC in C lang
grep, awk, sed, go
based on DFA (Deterministic Finite Automata)
simpler implementation
. Regex-directed
Larry Wall, perl, 1987
Perl-Compatible Regular Expressions (JS, Ruby, .Net,...)
based on NFA (Nondeterministic Finite Automata)
broader feature set