From c19b11e11528c60f5f3c7d1c73a07b6793f2551a Mon Sep 17 00:00:00 2001
From: bth <git@bth.moi>
Date: Sun, 18 Jan 2026 20:17:40 -0800
Subject: [PATCH] flags.ValidValueOrExit and os.Exit on Help

---
 flags/flags.go | 12 +++++++++---
 next/next.go   |  7 +++----
 sort/sort.go   | 19 +++++++++----------
 tag/tag.go     | 15 +++++++++------
 um.go          |  3 ++-
 5 files changed, 32 insertions(+), 24 deletions(-)

diff --git a/flags/flags.go b/flags/flags.go
index 4d79115..72eafad 100644
--- a/flags/flags.go
+++ b/flags/flags.go
@@ -52,15 +52,20 @@ func HasDashPrefix(s string) bool {
 	return strings.HasPrefix(s, "-")
 }
 
-func MissingValueArg(args []string, i int) bool {
+func MissingValue(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)
+// if no value ahead in the args, print error and exit
+func ValidValueOrExit(args []string, i int) {
+	if MissingValue(args, i) {
+		fmt.Printf("%s needs a value assignment\n", args[i])
+		os.Exit(1)
+	}
 }
 
 // print out help string by reflecting over fields of provided opts struct
+// and os.Exit(0)
 func Help(subcmd string, opts any) {
 	v := reflect.ValueOf(opts)
 	t := v.Type()
@@ -89,4 +94,5 @@ func Help(subcmd string, opts any) {
 	}
 	fmt.Printf("um %s%s\n", subcmd, positional)
 	w.Flush()
+	os.Exit(0)
 }
diff --git a/next/next.go b/next/next.go
index bd7da6d..fbfa19a 100644
--- a/next/next.go
+++ b/next/next.go
@@ -2,7 +2,6 @@ package next
 
 import (
 	"fmt"
-	"os"
 
 	"github.com/brtholomy/um/go/flags"
 )
@@ -31,15 +30,15 @@ func parseArgs(args []string) options {
 			opts.Tags.Val = arg
 		case i >= 2:
 			fmt.Println("um next : too many args")
-			os.Exit(1)
+			flags.Help("next", opts)
 		case arg == opts.Help.Long || arg == opts.Help.Short:
 			flags.Help("next", opts)
-			return opts
 		}
 	}
 	return opts
 }
 
 func Next(args []string) {
-	_ = parseArgs(args)
+	opts := parseArgs(args)
+	fmt.Println(opts)
 }
diff --git a/sort/sort.go b/sort/sort.go
index 2827656..6a19a18 100644
--- a/sort/sort.go
+++ b/sort/sort.go
@@ -1,6 +1,8 @@
 package sort
 
 import (
+	"fmt"
+
 	"github.com/brtholomy/um/go/flags"
 )
 
@@ -23,25 +25,22 @@ func parseArgs(args []string) options {
 	for i, arg := range args {
 		switch {
 		case arg == opts.Source.Long || arg == opts.Source.Short:
-			if flags.MissingValueArg(args, i) {
-				flags.HelpMissingVal(arg)
-				break
-			}
+			flags.ValidValueOrExit(args, i)
 			opts.Source.Val = args[i+1]
 		case arg == opts.Key.Long || arg == opts.Key.Short:
-			if flags.MissingValueArg(args, i) {
-				flags.HelpMissingVal(arg)
-				break
-			}
+			flags.ValidValueOrExit(args, i)
 			opts.Key.Val = args[i+1]
 		case arg == opts.Help.Long || arg == opts.Help.Short:
 			flags.Help("sort", opts)
-			return opts
+		default:
+			fmt.Println("invalid argument")
+			flags.Help("sort", opts)
 		}
 	}
 	return opts
 }
 
 func Sort(args []string) {
-	_ = parseArgs(args)
+	opts := parseArgs(args)
+	fmt.Println(opts)
 }
diff --git a/tag/tag.go b/tag/tag.go
index f335a09..6f2bfb1 100644
--- a/tag/tag.go
+++ b/tag/tag.go
@@ -1,6 +1,8 @@
 package tag
 
 import (
+	"fmt"
+
 	"github.com/brtholomy/um/go/flags"
 )
 
@@ -29,19 +31,20 @@ 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:
-			if flags.MissingValueArg(args, i) {
-				flags.HelpMissingVal(arg)
-				break
-			}
+			// TODO: should we use reflection here for a general Valid(arg, opts.Field)?
+			flags.ValidValueOrExit(args, i)
 			opts.Date.Val = args[i+1]
 		case arg == opts.Help.Long || arg == opts.Help.Short:
 			flags.Help("tag", opts)
-			return opts
+		default:
+			fmt.Println("invalid argument")
+			flags.Help("tag", opts)
 		}
 	}
 	return opts
 }
 
 func Tag(args []string) {
-	_ = parseArgs(args)
+	opts := parseArgs(args)
+	fmt.Println(opts)
 }
diff --git a/um.go b/um.go
index fcbbb36..e2a485c 100644
--- a/um.go
+++ b/um.go
@@ -18,7 +18,7 @@ const (
 	sort Subcommand = "sort"
 )
 
-var help string = fmt.Sprintf("um [%s | %s | %s | %s]", tag, next, last, sort)
+var help string = fmt.Sprintf("um [%s | %s | %s | %s] [--help | -h]", tag, next, last, sort)
 
 func main() {
 	// TODO: do something useful:
@@ -41,6 +41,7 @@ func main() {
 	case sort:
 		sortpkg.Sort(args)
 	default:
+		fmt.Println("command not found")
 		fmt.Println(help)
 		os.Exit(1)
 	}