package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)^(?!(?:[^A\n]*A){2})(?!(?:[^B\n]*B){3})(?!(?:[^C\n]*C){2})(?!(?:[^D\n]*D){2})(?:[ABCD](?:\s|$)){3}`)
var str = `# These are valid:
A B C
A B B
B C B
D A B
# These are invalid:
A A B
B B B`
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/