refine Usage to print last command help

zuoxf1 · zuoxf1 · commit 342360893a03 · 2019-08-29T18:51:44.000+08:00
diff --git a/argparse.go b/argparse.go
@@ -19,6 +19,7 @@ type Command struct {
 	args        []*arg
 	commands    []*Command
 	parsed      bool
+	happened    bool
 	parent      *Command
 }
 
@@ -255,7 +256,7 @@ func (o *Command) Selector(short string, long string, options []string, opts *Op
 // Happened shows whether Command was specified on CLI arguments or not. If Command did not "happen", then
 // all its descendant commands and arguments are not parsed. Returns a boolean value.
 func (o *Command) Happened() bool {
-	return o.parsed
+	return o.happened
 }
 
 // Usage returns a multiline string that is the same as a help message for this Parser or Command.
@@ -266,6 +267,11 @@ func (o *Command) Happened() bool {
 // Accepts an interface that can be error, string or fmt.Stringer that will be prepended to a message.
 // All other interface types will be ignored
 func (o *Command) Usage(msg interface{}) string {
+	for _, cmd := range o.commands {
+		if cmd.Happened() {
+			return cmd.Usage(msg)
+		}
+	}
 	var result string
 	// Stay classy
 	maxWidth := 80
diff --git a/command.go b/command.go
@@ -63,6 +63,9 @@ func (o *Command) parse(args *[]string) error {
 		}
 	}
 
+	// Set happened status to true when command happend
+	o.happened = true
+
 	// Reduce arguments by removing Command name
 	*args = (*args)[1:]
 

Original file line number	Diff line number	Diff line change
`@@ -63,6 +63,9 @@ func (o Command) parse(args []string) error {`
`63`	`63`	`}`
`64`	`64`	`}`
`65`	`65`
	`66`	`+ // Set happened status to true when command happend`
	`67`	`+ o.happened = true`
	`68`	`+`
`66`	`69`	`// Reduce arguments by removing Command name`
`67`	`70`	`args = (args)[1:]`
`68`	`71`