Add ParseScope function

ldap/parse.go

+package ldaputil
+
+import (
+	"fmt"
+
+	"gopkg.in/ldap.v2"
+)
+
+func ParseScope(s string) (int, error) {
+	switch s {
+	case "base":
+		return ldap.ScopeBaseObject, nil
+	case "one":
+		return ldap.ScopeSingleLevel, nil
+	case "sub":
+		return ldap.ScopeWholeSubtree, nil
+	default:
+		return 0, fmt.Errorf("unknown LDAP scope '%s'", s)
+	}
+}