Add is.Digit to scan

scan/is/is.go

@@ -49,10 +49,10 @@ type Min struct {
 	This any
 }
 
-// X scannable struct represents exactly X number of the given scannable
+// N scannable struct represents exactly X number of the given scannable
 // items (This).
-type X struct {
-	X    int
+type N struct {
+	N    int
 	This any
 }
 
@@ -67,3 +67,4 @@ type Rng struct {
 //                    (keep most common to the left)
 
 var WS = In{' ', '\n', '\t', '\r'}
+var Digit = Rng{0, 9}

scan/scan.go

@@ -359,8 +359,8 @@ func (s *Scanner) Expect(scannables ...any) (*Cur, error) {
 			}
 			end = last
 
-		case is.X: // ------------------------------------------------------
-			m, err := s.Expect(is.MMx{v.X, v.X, v.This})
+		case is.N: // ------------------------------------------------------
+			m, err := s.Expect(is.MMx{v.N, v.N, v.This})
 			if err != nil {
 				s.Jump(beg)
 				return nil, s.ErrorExpected(v)
@@ -420,9 +420,9 @@ func (s *Scanner) ErrorExpected(this any, args ...any) error {
 	case is.MMx:
 		str := `expected min %v, max %v of %q`
 		msg = fmt.Sprintf(str, v.Min, v.Max, v.This)
-	case is.X:
+	case is.N:
 		str := `expected exactly %v of %q`
-		msg = fmt.Sprintf(str, v.X, v.This)
+		msg = fmt.Sprintf(str, v.N, v.This)
 	case is.Rng:
 		str := `expected range [%v-%v]`
 		msg = fmt.Sprintf(str, string(v.First), string(v.Last))