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// experiment · 2026-06-20
Type a regex and a test string, then watch a hand-built backtracking engine try, fail, and recoil along a live railroad diagram — capture groups fill with a blue wash, and catastrophic backtracking erupts into a visible storm you can scrub through step by step.
// watch the engine try, fail, and backtrack — step through a regex match
// enter group 1 @0
// hand-rolled recursive-descent parser + backtracking matcher · subset: literals · . · [ranges/^neg] · * + ? {n,m} (lazy ?) · | · ( ) · ^ $ · \d\w\s · step cap 50,000