flags rewrite : just well defined structs and a clear switch block

flags/flags.go

@@ -5,20 +5,34 @@ import (
 	"strings"
 )
 
-type Flag string
-
-func (f Flag) Dash() string {
-	return fmt.Sprintf("--%s", f)
+type Arg struct {
+	Val  string
+	Help string
 }
 
-// prepend --flag to args if a flag isn't there:
-// allows trailing flags:
-// um tag foo --invert
-// becomes:
-// um tag --query foo --invert
-func PrependFlagToArgs(args []string, flag Flag) []string {
-	if len(args) >= 1 && !strings.HasPrefix(args[0], "-") {
-		args = append([]string{flag.Dash()}, args...)
-	}
-	return args
+type Flag struct {
+	Long  string
+	Short string
+	Val   string
+	Help  string
+}
+
+// there's got to be a way to generalize the val field to string|bool
+type FlagBool struct {
+	Long  string
+	Short string
+	Val   bool
+	Help  string
+}
+
+func HasDashPrefix(s string) bool {
+	return strings.HasPrefix(s, "-")
+}
+
+func MissingValueArg(args []string, i int) bool {
+	return i+1 == len(args) || HasDashPrefix(args[i+1])
+}
+
+func HelpMissingVal(flag string) {
+	fmt.Printf("%s needs a value assignment\n", flag)
 }