Move argument parsing to separate file/function

2 files changed, 37 insertions, 13 deletions

diff --git a/args.go b/args.go
new file mode 100644
index 0000000..adcaa6b
--- /dev/null
+++ b/args.go
@@ -0,0 +1,32 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"strconv"
+)
+
+// The arguments to this program
+type args struct {
+	Radix uint
+}
+
+func parseArgs() (args, error) {
+	if len(os.Args) == 2 {
+		if radix, err := strconv.ParseUint(os.Args[1], 0, 0); err == nil {
+			if radix > 1 {
+				return args{uint(radix)}, nil
+			} else {
+				return args{}, errors.New("Radix must be an integer above 1.")
+			}
+		} else {
+			return args{}, fmt.Errorf(
+				"Argument must be an integer above 1 [%w].", err)
+		}
+	} else if len(os.Args) < 2 {
+		return args{}, errors.New("Please provide an argument (radix to study).")
+	} else {
+		return args{}, errors.New("Too many arguments provided.")
+	}
+}
diff --git a/radix_info.go b/radix_info.go
index 32e1e40..386c050 100644
--- a/radix_info.go
+++ b/radix_info.go
@@ -3,22 +3,14 @@ package main
 import (
 	"fmt"
 	"os"
-	"strconv"
 )
 
 func main() {
-	if len(os.Args) > 1 {
-		if n, err := strconv.ParseUint(os.Args[1], 0, 0); err == nil {
-			if n > 1 {
-				factorInfo := GetFactorInfo(uint(n))
-				factorInfo.WriteTo(os.Stdout)
-			} else {
-				fmt.Println("Argument must be an integer above 1.")
-			}
-		} else {
-			fmt.Printf("Argument must be an integer above 1 [%v].\n", err)
-		}
+	args, err := parseArgs()
+	if err == nil {
+		factorInfo := GetFactorInfo(args.Radix)
+		factorInfo.WriteTo(os.Stdout)
 	} else {
-		fmt.Println("Please provide an argument (radix to study).")
+		fmt.Fprintln(os.Stderr, err)
 	}
 }