regex engine lexer · parser · NFA · DFA · matcher
tokens–
NFA states–
DFA states–
compile–
match–
result–
Thompson NFA — ε edges dashed
DFA — subset construction. Hover a state to see its NFA set.
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Compares Thompson NFA simulation vs. compiled DFA throughput on the current pattern/input. DFA is typically 5–50× faster and immune to catastrophic backtracking.