Rockingcool/kleingrep
2
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Started working on '+' operator

Browse Source
This commit is contained in:
Aadhavan Srinivasan
2024-10-24 14:39:28 -04:00
parent c894ee4c0d
commit 139c88dd58
2 changed files with 9 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
main.go
View File

@@ -11,7 +11,7 @@ import (
const CONCAT rune = '~' const CONCAT rune = '~'
func isOperator(c rune) bool { func isOperator(c rune) bool {
if c == '*' || c == '|' || c == CONCAT { if c == '+' || c == '*' || c == '|' || c == CONCAT {
return true return true
} }
return false return false
@@ -19,7 +19,7 @@ func isOperator(c rune) bool {
/* priority returns the priority of the given operator */ /* priority returns the priority of the given operator */
func priority(op rune) int { func priority(op rune) int {
precedence := []rune{'|', CONCAT, '*'} precedence := []rune{'|', CONCAT, '+', '*'}
return slices.Index(precedence, op) return slices.Index(precedence, op)
} }
@@ -138,6 +138,8 @@ func thompson(re string) *State {
} }
stateToAdd.transitions[s1.content] = append(stateToAdd.transitions[s1.content], s1) stateToAdd.transitions[s1.content] = append(stateToAdd.transitions[s1.content], s1)
nfa = append(nfa, stateToAdd) nfa = append(nfa, stateToAdd)
case '+':
case '|': case '|':
s1 := pop(&nfa) s1 := pop(&nfa)
s2 := pop(&nfa) s2 := pop(&nfa)

7
matching.go
View File

@@ -40,15 +40,16 @@ func findAllMatchesHelper(start *State, str string, indices []matchIndex, offset
currentStates := make([]*State, 0) currentStates := make([]*State, 0)
tempStates := make([]*State, 0) // Used to store states that should be used in next loop iteration tempStates := make([]*State, 0) // Used to store states that should be used in next loop iteration
i := 0 // Index in string i := 0 // Index in string
startingFrom := i // Store starting index
// Increment until we hit a character matching the start state (assuming not 0-state) // Increment until we hit a character matching the start state (assuming not 0-state)
if start.isEmpty == false { if start.isEmpty == false {
for i < len(str) && int(str[i]) != start.content { for i < len(str) && int(str[i]) != start.content {
i++ i++
} }
startIdx = i startIdx = i
startingFrom = i
i++ // Advance to next character (if we aren't at a 0-state, which doesn't match anything), so that we can check for transitions. If we advance at a 0-state, we will never get a chance to match the first character i++ // Advance to next character (if we aren't at a 0-state, which doesn't match anything), so that we can check for transitions. If we advance at a 0-state, we will never get a chance to match the first character
} }
startingFrom := i
currentStates = append(currentStates, start) currentStates = append(currentStates, start)
// Main loop // Main loop
@@ -57,6 +58,7 @@ func findAllMatchesHelper(start *State, str string, indices []matchIndex, offset
zeroStates := make([]*State, 0) zeroStates := make([]*State, 0)
// Keep taking zero-states, until there are no more left to take // Keep taking zero-states, until there are no more left to take
// Objective: If any of our current states have transitions to 0-states, replace them with the 0-state. Do this until there are no more transitions to 0-states
zeroStates, isZero := takeZeroState(currentStates) zeroStates, isZero := takeZeroState(currentStates)
tempStates = append(tempStates, zeroStates...) tempStates = append(tempStates, zeroStates...)
for isZero == true { for isZero == true {
@@ -105,7 +107,8 @@ func findAllMatchesHelper(start *State, str string, indices []matchIndex, offset
tempStates = nil tempStates = nil
for _, state := range currentStates { for _, state := range currentStates {
if state.isLast { // Only add the match if we the start index is in bounds
if state.isLast && startIdx+offset < len(str)+offset {
endIdx = i endIdx = i
indices = append(indices, matchIndex{startIdx + offset, endIdx + offset}) indices = append(indices, matchIndex{startIdx + offset, endIdx + offset})
} }