Add captured alias declaration types

registry.go

@@ -1,19 +1,46 @@
 package commandkit
 
-import "fmt"
+import (
+	"errors"
+	"fmt"
+)
 
-// Register adds a batch of root commands to the application. The complete batch
+// Register adds a batch of declarations to the application. The complete batch
 // is validated before registry mutation; on error the registry and its derived
 // command metadata remain unchanged. A successful nonempty batch becomes
-// visible to later invocations. Command declarations remain reusable.
-func (a *App) Register(commands ...Command) error {
-	return a.installBatch(commands...)
+// visible to later invocations. Declarations remain reusable.
+func (a *App) Register(declarations ...Declaration) error {
+	return a.installBatch(declarations...)
 }
 
-func (a *App) installBatch(commands ...Command) error {
+func (a *App) installBatch(declarations ...Declaration) error {
 	if a == nil {
 		return fmt.Errorf("cannot register commands on a nil app")
 	}
+	commands := make([]Command, 0, len(declarations))
+	rules := make([]RoutingRule, 0)
+	for _, declaration := range declarations {
+		switch value := declaration.(type) {
+		case Command:
+			commands = append(commands, value)
+		case *Command:
+			if value == nil {
+				return fmt.Errorf("nil *Command declaration")
+			}
+			commands = append(commands, *value)
+		case RoutingRule:
+			rules = append(rules, value)
+		case *RoutingRule:
+			if value == nil {
+				return fmt.Errorf("nil *RoutingRule declaration")
+			}
+			rules = append(rules, *value)
+		case nil:
+			return fmt.Errorf("nil declaration")
+		default:
+			return fmt.Errorf("unsupported declaration type %T", declaration)
+		}
+	}
 
 	pending := make(map[string]*commandNode, len(commands))
 	for _, command := range commands {
@@ -32,7 +59,15 @@ func (a *App) installBatch(commands ...Command) error {
 		}
 		pending[name] = &commandNode{command: command}
 	}
-	if len(pending) == 0 {
+	for _, rule := range rules {
+		if rule.record == nil {
+			return fmt.Errorf("invalid zero routing rule declaration")
+		}
+		if len(rule.record.issues) > 0 {
+			return fmt.Errorf("routing rule: %w", errors.Join(rule.record.issues...))
+		}
+	}
+	if len(pending) == 0 && len(rules) == 0 {
 		return nil
 	}
 	if a.commands == nil {
@@ -41,6 +76,9 @@ func (a *App) installBatch(commands ...Command) error {
 	for name, node := range pending {
 		a.commands[name] = node
 	}
-	a.snapshot = nil
+	a.routingRules = append(a.routingRules, rules...)
+	if len(pending) > 0 {
+		a.snapshot = nil
+	}
 	return nil
 }