Add help command to script/extension.

lib/radiant/extension/script.rb

@@ -121,11 +121,11 @@ class Git < Checkout
     def checkout_command
       "git clone #{url} #{name}"
     end
-    
+
     def abstract?
       false
     end
-    
+
     def matches?
       self.url =~ /\.?git/
     end
@@ -175,7 +175,7 @@ class Extension
     module Script
       class << self
         def execute(args)
-          command = args.shift
+          command = args.shift || 'help'
           const_get(command.camelize).new(args)
         end
       end
@@ -232,6 +232,67 @@ def initialize(args=[])
           end
         end
       end
+
+      class Help
+        include Util
+        def initialize(args=[])
+          helpcmd = args.shift || 'basic'
+          send helpcmd
+        end
+
+        def basic
+          output <<-HELP
+          Usage: script/extension [command] [arguments]
+
+            Commands:
+
+              install     Install an extension from the registry.
+              uninstall   Uninstall a previously installed extension.
+              help        Display help for commands
+
+          Type 'script/extension help [command]' for information about that
+          command.
+          HELP
+        end
+        alias :help :basic
+
+        def install
+          output <<-HELP
+          Usage: script/extension install extension_name
+
+            - Installs an extension from the information in the registry.
+
+          HELP
+        end
+
+        def uninstall
+          output <<-HELP
+          Usage: script/extension uninstall extension_name
+
+            - Uninstalls a previously installed extension.
+
+          HELP
+        end
+
+        private
+          def output(string='')
+            $stdout.puts strip_leading_whitespace(string)
+          end
+
+          def strip_leading_whitespace(text)
+            text = text.dup
+            text.gsub!("\t", "  ")
+            lines = text.split("\n")
+            leading = lines.map do |line|
+              unless line =~ /^\s*$/
+                 line.match(/^(\s*)/)[0].length
+              else
+                nil
+              end
+            end.compact.min
+            lines.inject([]) {|ary, line| ary << line.sub(/^[ ]{#{leading}}/, "")}.join("\n")
+          end
+      end
     end
   end
 end

spec/lib/radiant/extension/script_spec.rb

@@ -8,12 +8,20 @@
 
     Radiant::Extension::Script::Uninstall.should_receive(:new)
     Radiant::Extension::Script.execute ['uninstall']
+
+    Radiant::Extension::Script::Help.should_receive(:new)
+    Radiant::Extension::Script.execute ['help']
   end
 
   it "should pass the command-line args to the subscript" do
     Radiant::Extension::Script::Install.should_receive(:new).with(['page_attachments'])
     Radiant::Extension::Script.execute ['install', 'page_attachments']
   end
+
+  it "should run the help command if no command is passed" do
+    Radiant::Extension::Script::Help.should_receive(:new).with([])
+    Radiant::Extension::Script.execute []
+  end
 end
 
 describe "Radiant::Extension::Script::Util" do
@@ -98,6 +106,17 @@
   end
 end
 
+
+describe "Radiant::Extension::Script::Help" do
+  it "should output a help message for each command" do
+    messages = %w{basic install uninstall help}
+    $stdout.should_receive(:puts).exactly(messages.size).times
+    messages.each do |m|
+      Radiant::Extension::Script::Help.new([m])
+    end
+  end
+end
+
 describe "Registry::Action" do
   before :each do
     @action = Registry::Action.new