Add ability to programmatically add options to a group

Author: peterebden

group.go

@@ -73,6 +73,13 @@ func (g *Group) AddGroup(shortDescription string, longDescription string, data i
 	return group, nil
 }
 
+// AddOption adds a new option to this group.
+func (g *Group) AddOption(option *Option, value reflect.Value) {
+	option.value = value
+	option.group = g
+	g.options = append(g.options, option)
+}
+
 // Groups returns the list of groups embedded in this group.
 func (g *Group) Groups() []*Group {
 	return g.groups

group_test.go

@@ -1,6 +1,7 @@
 package flags
 
 import (
+	"reflect"
 	"testing"
 )
 
@@ -253,3 +254,19 @@ func TestFindOptionByShortFlagInSubGroup(t *testing.T) {
 		t.Errorf("Expected 't', but got %v", opt.ShortName)
 	}
 }
+
+func TestAddOptionNonOptional(t *testing.T) {
+	var opts struct {
+		Test bool
+	}
+	p := NewParser(&opts, Default)
+	p.AddOption(&Option{
+		LongName: "test",
+	}, reflect.ValueOf(&opts.Test))
+	_, err := p.ParseArgs([]string{"--test"})
+	if err != nil {
+		t.Errorf("unexpected error: %s", err)
+	} else if !opts.Test {
+		t.Errorf("option not set")
+	}
+}