Thanks Raul, your response to my worries is, as always, fast and precise. You are able to elucidate the problem and motivate us to get the answers by ourselves, that's quite something! I'm not used to work with the Rails debugger, but already looking for some resources to be able to understand it as soon as possible.
Buon Natale! Cheers! 2008/12/9 raul parolari <[EMAIL PROTECTED]> > > Gabriel, > > this type of problems is the most common occurrence when building an > application; "*a variable is nil somewhere.*.". It is quite important that > you do something more than reading the trace. > > The trace tells you that this happens when calling > "select_country_choices"...; this method is one liner in a helper module, > and it is accessing one variable (@countries). > > So, the question you should be asking is: is @countries nil? let's put a > debug statement somewhere before the call that produces the exception. > > And if you find that it is nil, the next step is: *who should set it?* the > call is from the students_helper, so it is likely that the code is in the > Students Controller... ah, the method to provide @countries is there, but > *is someone calling it*? (If not this is the problem; the guy who wrote > the tutorial forgot to mention that this method should be called.. let's > see: *where should I put the call?* in all the actions that need it? uhm, > I remember this thing about "filters"...). > > This is the process that you should follow next time (I know that you are > able to); not stop at the exception and say "it does not work". Anyone one > can do a "homework", following mechanically the example; but this is not > mechanical, and so it is a lot more useful. > ------- > > Having said that, in the tutorial I forgot to mention that you need a > before_filter in the students_controller: > > before_filter :countries, :only => [ :new, :edit, :update, :create ] > > By the way, the line is in the zip of the project (the link is in section > "2. An international Online College"). > > In any case, kudos for following line by line the construction of the > project (you are probably one of the few, if not the only one, who tried > that). But I invite you to do something more next time; if there is an > error, dive into it, and see if you can fix it... or at least go near to the > exact reason. The feeling will be special, > > Raul > > > On Tue, Dec 9, 2008 at 7:24 AM, Gabriel <[EMAIL PROTECTED]> wrote: > >> Hi folks. >> I'm following the Action View Helpers tutorial but something's going >> wrong. >> >> Everything goes well until step 2.5, where we populate the database with >> some sample data. >> >> When I run the application, I can view the "index" and "show" views, but >> the "edit" and "new" views (where the 'editable_student_form' partial is >> rendered), I'm getting a "NoMethodError" when calling >> "select_country_choices" (at least is where the trace stops). >> >> The error message is: >> >> You have a nil object when you didn't expect it! >> You might have expected an instance of Array. >> The error occurred while evaluating nil.map" >> >> I'm not getting the "select_country_choices" when I call "Student.methods" >> or "StudentsHelper.methods" in Rails Console as well. >> >> How can I get things right? >> >> Thanks, >> Gabriel. >> >> >> >> > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "ruby-on-rails-programming-with-passion" group. To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/ruby-on-rails-programming-with-passion?hl=en?hl=en -~----------~----~----~----~------~----~------~--~---
