Made lookarounds a little more efficient by only matching from (or to, in the case of lookbehind) the current index
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14
nfa.go
14
nfa.go
@@ -118,15 +118,21 @@ func (s State) checkAssertion(str []rune, idx int) bool {
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if s.isLookaround() {
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// The process here is simple:
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// 1. Compile the regex stored in the state's contents.
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// 2. Run it on the test string.
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// 2. Run it on a subset of the test string, that ends after the current index in the string
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// 3. Based on the kind of lookaround (and the indices we get), determine what action to take.
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startState := s.lookaroundNFA
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matchIndices := findAllMatches(startState, str, startState.lookaroundNumCaptureGroups)
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var strToMatch []rune
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if s.assert == PLA || s.assert == NLA {
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strToMatch = str[idx:]
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} else {
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strToMatch = str[:idx]
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}
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matchIndices := findAllMatches(startState, strToMatch, startState.lookaroundNumCaptureGroups)
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numMatchesFound := 0
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for _, matchIdx := range matchIndices {
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if s.assert == PLA || s.assert == NLA { // Lookahead - return true (or false) if at least one match starts at the current index
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if matchIdx[0].startIdx == idx {
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if s.assert == PLA || s.assert == NLA { // Lookahead - return true (or false) if at least one match starts at 0. Zero is used because the test-string _starts_ from idx.
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if matchIdx[0].startIdx == 0 {
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numMatchesFound++
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}
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}
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