notes_app¶ ↑

Toy notetaking app. Tracker project at: www.pivotaltracker.com/projects/618957/stories#

Debugger¶ ↑

Debugger support is available through the debugger command when you start your Mongrel or WEBrick server with –debugger. This means that you can break out of execution at any point in the code, investigate and change the model, and then, resume execution! You need to install ruby-debug to run the server in debugging mode. With gems, use sudo gem install ruby-debug. Example:

class WeblogController < ActionController::Base
  def index
    @posts = Post.all
    debugger
  end
end

So the controller will accept the action, run the first line, then present you with a IRB prompt in the server window. Here you can do things like:

>> @posts.inspect
=> "[#<Post:0x14a6be8
        @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}>,
     #<Post:0x14a6620
        @attributes={"title"=>"Rails", "body"=>"Only ten..", "id"=>"2"}>]"
>> @posts.first.title = "hello from a debugger"
=> "hello from a debugger"

…and even better, you can examine how your runtime objects actually work:

>> f = @posts.first
=> #<Post:0x13630c4 @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}>
>> f.
Display all 152 possibilities? (y or n)

Finally, when you’re ready to resume execution, you can enter “cont”.