command: add flag convenience function

pkg/command/command.go

@@ -20,3 +20,10 @@ type Command struct {
 	} `yaml:"completion,omitempty" json:"completion,omitempty" jsonschema_description:"Completion definition"`
 	Commands []Command `yaml:"commands,omitempty" json:"commands,omitempty" jsonschema_description:"Subcommands of the command"`
 }
+
+func (c *Command) AddFlag(f Flag) {
+	if c.Flags == nil {
+		c.Flags = make(map[string]string)
+	}
+	c.Flags[f.format()] = f.Usage
+}

pkg/command/flag.go

@@ -0,0 +1,48 @@
+package command
+
+type Flag struct {
+	Longhand   string
+	Shorthand  string
+	Usage      string
+	Repeatable bool
+	Optarg     bool
+	Value      bool
+	Hidden     bool
+	Required   bool
+}
+
+func (f Flag) format() string {
+	var s string
+
+	if f.Shorthand != "" {
+		s += f.Shorthand
+		if f.Longhand != "" {
+			s += ", "
+		}
+	}
+
+	if f.Longhand != "" {
+		s += f.Longhand
+	}
+
+	switch {
+	case f.Optarg:
+		s += "?"
+	case f.Value:
+		s += "="
+	}
+
+	if f.Repeatable {
+		s += "*"
+	}
+
+	if f.Required {
+		s += "!"
+	}
+
+	if f.Hidden {
+		s += "&"
+	}
+
+	return s
+}