Refactor parseSpelledDigit to parseDigit and handle both spelled digits and regular digits

day1/part2.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -20,7 +21,7 @@ func readInput() string {
 	return str
 }
 
-func parseSpelledDigit(input string) string {
+func parseDigit(input string) (string, error) {
 	digits := map[string]string{
 		"one":   "1",
 		"two":   "2",
@@ -31,21 +32,30 @@ func parseSpelledDigit(input string) string {
 		"seven": "7",
 		"eight": "8",
 		"nine":  "9",
+		"1":     "1",
+		"2":     "2",
+		"3":     "3",
+		"4":     "4",
+		"5":     "5",
+		"6":     "6",
+		"7":     "7",
+		"8":     "8",
+		"9":     "9",
 	}
 	i, ok := digits[input]
 	if ok == false {
-		return "-1"
+		return "", errors.New("No spelled digit")
 	}
-	return i
+	return i, nil
 }
 
-func addSDStrings(input1 string, input2 string) string {
-	num1 := parseSpelledDigit(input1)
-	if num1 == "-1" {
+func addDStrings(input1 string, input2 string) string {
+	num1, err := parseDigit(input1)
+	if err != nil {
 		num1 = input1
 	}
-	num2 := parseSpelledDigit(input2)
-	if num2 == "-1" {
+	num2, err := parseDigit(input2)
+	if err != nil {
 		num2 = input2
 	}
 	num_str := num1 + num2
@@ -64,16 +74,10 @@ func main() {
 		}
 		first := matches[0]
 		last := matches[matches_len-1]
-		num_str := first + " " + last
+		num_str := addDStrings(first, last)
 		num, err := strconv.Atoi(num_str)
 		if err != nil {
-			num_str = addSDStrings(first, last)
-			num, err = strconv.Atoi(num_str)
-			if err != nil {
-				log.Fatalln(err)
-				continue
-			}
-
+			log.Fatalln(err)
 		}
 		answer = answer + num
 		fmt.Println(l, first, last, num)