@ -3,7 +3,7 @@ package main
const EPSILON int = 0
type State struct {
content int // Contents of current state
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.
@ -22,19 +22,27 @@ func verifyLastStatesHelper(state *State, visited map[*State]bool) {
state . isLast = true
return
}
if len ( state . transitions ) == 1 && len ( state . transitions [ state . content ] ) == 1 && state . transitions [ state . content ] [ 0 ] == state { // Eg. a*
state . isLast = true
return
// if len(state.transitions) == 1 && len(state.transitions[state.content]) == 1 && state.transitions[state.content][0] == state { // Eg. a*
if len ( state . transitions ) == 1 { // Eg. a*
var moreThanOneTrans bool // Dummy variable, check if all the transitions for the current's state's contents have a length of one
for _ , c := range state . content {
if len ( state . transitions [ c ] ) != 1 || state . transitions [ c ] [ 0 ] != state {
moreThanOneTrans = true
}
}
state . isLast = ! moreThanOneTrans
}
if len ( state . transitions ) == 1 && state . isKleene { // A State representing a Kleene Star has a transition going out, which loops back to it. If that is the only transition (and it contains only one state), then it must be a last-state
for _ , v := range state . transitions { // Should only loop once
if len ( v ) == 1 {
if state . isKleene { // A State representing a Kleene Star has transitions going out, which loop back to it. If all those transitions point to the same (single) state, then it must be a last state
transitionDests := make ( [ ] * State , 0 )
for _ , v := range state . transitions {
transitionDests = append ( transitionDests , v ... )
}
if allEqual ( transitionDests ... ) {
state . isLast = true
return
}
}
}
if visited [ state ] == true {
return
}
@ -55,7 +63,9 @@ func verifyLastStates(start []*State) {
func concatenate ( s1 * State , s2 * State ) * State {
for i := range s1 . output {
s1 . output [ i ] . transitions [ s2 . content ] , _ = unique_append ( s1 . output [ i ] . transitions [ s2 . content ] , s2 )
for _ , c := range s2 . content { // Create transitions for every element in s2's content to s2'
s1 . output [ i ] . transitions [ c ] , _ = unique_append ( s1 . output [ i ] . transitions [ c ] , s2 )
}
}
s1 . output = s2 . output
return s1
@ -64,14 +74,18 @@ func concatenate(s1 *State, s2 *State) *State {
func kleene ( s1 State ) * State {
toReturn := & State { }
toReturn . transitions = make ( map [ int ] [ ] * State )
toReturn . content = EPSILON
toReturn . content = newContents ( EPSILON )
toReturn . isEmpty = true
toReturn . isKleene = true
toReturn . output = append ( toReturn . output , toReturn )
for i := range s1 . output {
s1 . output [ i ] . transitions [ toReturn . content ] , _ = unique_append ( s1 . output [ i ] . transitions [ toReturn . content ] , toReturn )
for _ , c := range toReturn . content {
s1 . output [ i ] . transitions [ c ] , _ = unique_append ( s1 . output [ i ] . transitions [ c ] , toReturn )
}
}
for _ , c := range s1 . content {
toReturn . transitions [ c ] , _ = unique_append ( toReturn . transitions [ c ] , & s1 )
}
toReturn . transitions [ s1 . content ] , _ = unique_append ( toReturn . transitions [ s1 . content ] , & s1 )
return toReturn
}
@ -85,9 +99,13 @@ func alternate(s1 *State, s2 *State) *State {
// For example, given the transition 'a', the state 's1' can only be mentioned once.
// This would lead to multiple instances of the same set of match indices, since both
// 's1' states would be considered to match.
toReturn . transitions [ s1 . content ] , _ = unique_append ( toReturn . transitions [ s1 . content ] , s1 )
toReturn . transitions [ s2 . content ] , _ = unique_append ( toReturn . transitions [ s2 . content ] , s2 )
toReturn . content = EPSILON
for _ , c := range s1 . content {
toReturn . transitions [ c ] , _ = unique_append ( toReturn . transitions [ c ] , s1 )
}
for _ , c := range s2 . content {
toReturn . transitions [ c ] , _ = unique_append ( toReturn . transitions [ c ] , s2 )
}
toReturn . content = newContents ( EPSILON )
toReturn . isEmpty = true
return toReturn