Added fields to state, to determine capturing group information. 0th group refers to entire match

master
Aadhavan Srinivasan 2 weeks ago
parent 822d1f319f
commit 11f7f1d746

@ -21,18 +21,22 @@ const (
)
type State struct {
content stateContents // Contents of current state
isEmpty bool // If it is empty - Union operator and Kleene star states will be empty
isLast bool // If it is the last state (acept state)
output []*State // The outputs of the current state ie. the 'outward arrows'. A union operator state will have more than one of these.
transitions map[int][]*State // Transitions to different states (maps a character (int representation) to a _list of states. This is useful if one character can lead multiple states eg. ab|aa)
isKleene bool // Identifies whether current node is a 0-state representing Kleene star
assert assertType // Type of assertion of current node - NONE means that the node doesn't assert anything
zeroMatchFound bool // Whether or not the state has been used for a zero-length match - only relevant for zero states
allChars bool // Whether or not the state represents all characters (eg. a 'dot' metacharacter). A 'dot' node doesn't store any contents directly, as it would take up too much space
except []rune // Only valid if allChars is true - match all characters _except_ the ones in this block. Useful for inverting character classes.
lookaroundRegex string // Only for lookaround states - Contents of the regex that the lookaround state holds
lookaroundNFA *State // Holds the NFA of the lookaroundRegex - if it exists
content stateContents // Contents of current state
isEmpty bool // If it is empty - Union operator and Kleene star states will be empty
isLast bool // If it is the last state (acept state)
output []*State // The outputs of the current state ie. the 'outward arrows'. A union operator state will have more than one of these.
transitions map[int][]*State // Transitions to different states (maps a character (int representation) to a _list of states. This is useful if one character can lead multiple states eg. ab|aa)
isKleene bool // Identifies whether current node is a 0-state representing Kleene star
assert assertType // Type of assertion of current node - NONE means that the node doesn't assert anything
zeroMatchFound bool // Whether or not the state has been used for a zero-length match - only relevant for zero states
allChars bool // Whether or not the state represents all characters (eg. a 'dot' metacharacter). A 'dot' node doesn't store any contents directly, as it would take up too much space
except []rune // Only valid if allChars is true - match all characters _except_ the ones in this block. Useful for inverting character classes.
lookaroundRegex string // Only for lookaround states - Contents of the regex that the lookaround state holds
lookaroundNFA *State // Holds the NFA of the lookaroundRegex - if it exists
lookaroundNumCaptureGroups int // Number of capturing groups if current node is a lookaround
groupBegin bool // Whether or not the node starts a capturing group
groupEnd bool // Whether or not the node ends a capturing group
groupNum int // Which capturing group the node starts / ends
}
// Clones the NFA starting from the given state.
@ -65,6 +69,9 @@ func cloneStateHelper(state *State, cloneMap map[*State]*State) *State {
allChars: state.allChars,
except: append([]rune{}, state.except...),
lookaroundRegex: state.lookaroundRegex,
groupEnd: state.groupEnd,
groupBegin: state.groupBegin,
groupNum: state.groupNum,
}
cloneMap[state] = clone
for i, s := range state.output {
@ -113,17 +120,17 @@ func (s State) checkAssertion(str []rune, idx int) bool {
// 2. Run it on the test string.
// 3. Based on the kind of lookaround (and the indices we get), determine what action to take.
startState := s.lookaroundNFA
matchIndices := findAllMatches(startState, str)
matchIndices := findAllMatches(startState, str, startState.lookaroundNumCaptureGroups)
numMatchesFound := 0
for _, matchIdx := range matchIndices {
if s.assert == PLA || s.assert == NLA { // Lookahead - return true (or false) if at least one match starts at the current index
if matchIdx.startIdx == idx {
if matchIdx[0].startIdx == idx {
numMatchesFound++
}
}
if s.assert == PLB || s.assert == NLB { // Lookbehind - return true (or false) if at least one match _ends_ at the current index.
if matchIdx.endIdx == idx {
if matchIdx[0].endIdx == idx {
numMatchesFound++
}
}

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