package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)^(?!.*([ACD]).*\1)(?!(?>.*?B){3})(?>[A-D] ){2}[A-D]$`)
var str = `A B C
A B B
B C B
D A B
A A B
B B B
B C C
`
for i, match := range re.FindAllString(str, -1) {
fmt.Println(match, "found at index", i)
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Golang, please visit: https://golang.org/pkg/regexp/