feat: print parent command name in subcommand's usage

examples/greet/welcome_command.cr

@@ -4,6 +4,8 @@ class WelcomeCommand < Cling::Command
     @summary = @description = "sends a friendly welcome message"
 
     add_argument "name", description: "the name of the person to greet", required: true
+    add_option 'h', "help", description: "sends help information"
+
     # this will inherit the header and footer properties
     @inherit_borders = true
     # this will NOT inherit the parent flag options

spec/formatter_spec.cr

@@ -19,16 +19,24 @@ class WelcomeCommand < Cling::Command
   def setup : Nil
     @name = "welcome"
     @summary = @description = "sends a friendly welcome message"
+
+    add_argument "name", description: "the name of the person to greet", required: true
+    add_option 'h', "help", description: "sends help information"
   end
 
   def run(arguments : Cling::Arguments, options : Cling::Options) : Nil
   end
 end
 
 command_with_subcommand = GreetCommand.new
-command_with_subcommand.add_command WelcomeCommand.new
-
 command_without_subcommand = GreetCommand.new
+
+subcommand = WelcomeCommand.new
+command_with_subcommand.add_command subcommand
+
+sub_subcommand = WelcomeCommand.new
+subcommand.add_command sub_subcommand
+
 formatter = Cling::Formatter.new
 
 describe Cling::Formatter do
@@ -92,6 +100,18 @@ describe Cling::Formatter do
     end.should eq "Usage:\n\tgreet <arguments> [options]\n\n"
   end
 
+  it "generates a usage section for subcommand" do
+    String.build do |io|
+      formatter.format_usage(subcommand, io)
+    end.should eq "Usage:\n\tgreet welcome <command> <arguments> [options]\n\n"
+  end
+
+  it "generates a usage section for nested subcommand" do
+    String.build do |io|
+      formatter.format_usage(sub_subcommand, io)
+    end.should eq "Usage:\n\tgreet welcome welcome <arguments> [options]\n\n"
+  end
+
   it "generates an arguments section" do
     String.build do |io|
       formatter.format_arguments(command_with_subcommand, io)

src/cling/formatter.cr

@@ -62,7 +62,10 @@ module Cling
       io << "Usage:"
 
       if command.usage.empty?
-        io << "\n\t" << command.name
+        io << "\n\t"
+
+        print_command_names(command, io)
+
         unless command.children.empty?
           io << " <command>"
         end
@@ -164,5 +167,15 @@ module Cling
       return unless footer = command.footer
       io << footer << "\n\n"
     end
+
+    # Recursively prints all command names, including parent commands.
+    private def print_command_names(command : Command, io : IO) : Nil
+      if parent = command.parent
+        print_command_names(parent, io)
+      end
+
+      io << " " if parent
+      io << command.name
+    end
   end
 end