//refine the candidate set based on the questions and answers provided
func refine(answers *rx.BitSet, qns []string, cand []*rx.DFA, expns []*rx.RegExParsed, dex []int) ([]*rx.DFA, []*rx.RegExParsed, []int) {
remain := make([]*rx.DFA, 0, len(cand))
express := make([]*rx.RegExParsed, 0, len(expns))
index := make([]int, 0, len(expns))
//iterate through all candidates
for i := 0; i < len(cand); i++ {
test := new(rx.BitSet) //initialize new bitset
for j := 0; j < len(qns); j++ { //ask all the questions
if cand[i].Accepts(qns[j]) != nil {
test.Set(j) //record answers
}
}
if test.Equals(answers) { //if test matches answers, keep this DFA
remain = append(remain, cand[i])
express = append(express, expns[i])
if len(dex) == 0 {
index = append(index, i)
} else {
index = append(index, dex[i])
if len(cand) < 20 {
fmt.Printf("%d ", dex[i])
}
}
}
}
fmt.Printf("\n")
return remain, express, index
}
//find the expression that corresponds to the question word
func findExpr(nextQn *rx.BitSet, e []*RegEx) string {
b := new(rx.BitSet)
for i := 0; i < len(e); i++ {
b.Set(e[i].Index)
if b.Equals(nextQn) {
return e[i].Rexpr
}
b.Clear(e[i].Index)
}
return ""
}