flags.ValidateIncrementFetchOrExit to handle value expecting Flag[string]

flags/flags.go

@@ -53,18 +53,27 @@ func HasDashPrefix(s string) bool {
 	return strings.HasPrefix(s, "-")
 }
 
-func MissingValue(args []string, i int) bool {
+// check for non-dashed value ahead in the args slice
+func missingValue(args []string, i int) bool {
 	return i+1 == len(args) || HasDashPrefix(args[i+1])
 }
 
 // if no value ahead in the args, print error and exit
-func ValidValueOrExit(args []string, i int) {
+func validValueOrExit(args []string, i int) {
-	if MissingValue(args, i) {
+	if missingValue(args, i) {
 		log.Printf("um: %s needs a value assignment\n", args[i])
 		log.Fatal("try: um [cmd] --help")
 	}
 }
 
+// 1. validate a Flag[string] by looking ahead in args, if missing, os.Exit(1)
+// 2. increment the i to skip that value and return
+// 3. fetch that value and return
+func ValidateIncrementFetchOrExit(args []string, i int) (int, string) {
+	validValueOrExit(args, i)
+	return i + 1, args[i+1]
+}
+
 // print out help string by reflecting over fields of provided opts struct
 // and os.Exit(0)
 func Help(subcmd string, opts any) {

sort/sort.go

@@ -34,13 +34,9 @@ func parseArgs(args []string) options {
 		arg := args[i]
 		switch {
 		case arg == opts.Source.Long || arg == opts.Source.Short:
-			flags.ValidValueOrExit(args, i)
+			i, opts.Source.Val = flags.ValidateIncrementFetchOrExit(args, i)
-			opts.Source.Val = args[i+1]
-			i++
 		case arg == opts.Key.Long || arg == opts.Key.Short:
-			flags.ValidValueOrExit(args, i)
+			i, opts.Key.Val = flags.ValidateIncrementFetchOrExit(args, i)
-			opts.Key.Val = args[i+1]
-			i++
 		case arg == opts.Write.Long || arg == opts.Write.Short:
 			opts.Write.Val = true
 		case arg == opts.Help.Long || arg == opts.Help.Short:

tag/tag.go

@@ -32,9 +32,7 @@ func parseArgs(args []string) options {
 		case arg == opts.Invert.Long || arg == opts.Invert.Short:
 			opts.Invert.Val = true
 		case arg == opts.Date.Long || arg == opts.Date.Short:
-			flags.ValidValueOrExit(args, i)
+			i, opts.Date.Val = flags.ValidateIncrementFetchOrExit(args, i)
-			opts.Date.Val = args[i+1]
-			i++
 		case arg == opts.Help.Long || arg == opts.Help.Short:
 			flags.Help("tag", opts)
 		default: