thr3ads.net - Rails - [Rails] Method_missing from Ruby for Rails book [Jul 2006]

If this information is useful, please help other people find it:
Share via:

Dark Ambient

2006-Jul-30 16:40 UTC

[Rails] Method_missing from Ruby for Rails book

I''m having a problem getting this example from the book to work:

class Cookbook
  attr_accessor :title, :author

  def initialize
    @recipes = []
  end

  def method_missing(m, *args, &block)
    @recipes.send(m, *args, &block)
  end
end

cb = Cookbook.new
cb << recipe_for_cake
cb << recipe_for_chicken
beef_dishes = cb.find_all {|recipes| recipe.main_ingredient == "beef"
}

I''m getting callable.rb:14: undefined local variable or method
`recipe_for_cake'' for main:Object (NameError) so apparently
method_missing is not working.

Stuart

dblack@wobblini.net

2006-Jul-30 17:27 UTC

head link

[Rails] Method_missing from Ruby for Rails book

Hi --

On Sun, 30 Jul 2006, Dark Ambient wrote:
> I''m having a problem getting this example from the book to work:
>
> class Cookbook
> attr_accessor :title, :author
>
> def initialize
>   @recipes = []
> end
>
> def method_missing(m, *args, &block)
>   @recipes.send(m, *args, &block)
> end
> end
>
> cb = Cookbook.new
> cb << recipe_for_cake
> cb << recipe_for_chicken
> beef_dishes = cb.find_all {|recipes| recipe.main_ingredient ==
"beef" }
>
> I''m getting callable.rb:14: undefined local variable or method
> `recipe_for_cake'' for main:Object (NameError) so apparently
> method_missing is not working.
method_missing is working -- it''s just not being called where you
think it is.

cb << recipe_for_cake is syntactic sugar for this:

   cb.<<(recipe_for_cake)

The "recipe_for_cake" expression is sitting at the top level of the
program, where there''s no method_missing defined.  So Ruby
doesn''t
know what you mean by it.


David

-- 
http://www.rubypowerandlight.com => Ruby/Rails training & consultancy
   ----> SEE SPECIAL DEAL FOR RUBY/RAILS USERS GROUPS! <-----
http://dablog.rubypal.com        => D[avid ]A[. ]B[lack''s][ Web]log
http://www.manning.com/black     => book, Ruby for Rails
http://www.rubycentral.org       => Ruby Central, Inc.

dblack@wobblini.net

2006-Jul-30 19:23 UTC

head link

[Rails] Method_missing from Ruby for Rails book

Hi --

On Sun, 30 Jul 2006, dblack@wobblini.net wrote:
> Hi --
>
> On Sun, 30 Jul 2006, Dark Ambient wrote:
>
>> I''m having a problem getting this example from the book to
work:
>> 
>> class Cookbook
>> attr_accessor :title, :author
>> 
>> def initialize
>>   @recipes = []
>> end
>> 
>> def method_missing(m, *args, &block)
>>   @recipes.send(m, *args, &block)
>> end
>> end
>> 
>> cb = Cookbook.new
>> cb << recipe_for_cake
>> cb << recipe_for_chicken
>> beef_dishes = cb.find_all {|recipes| recipe.main_ingredient ==
"beef" }
>> 
>> I''m getting callable.rb:14: undefined local variable or method
>> `recipe_for_cake'' for main:Object (NameError) so apparently
>> method_missing is not working.
>
> method_missing is working -- it''s just not being called where you
> think it is.
>
> cb << recipe_for_cake is syntactic sugar for this:
>
>  cb.<<(recipe_for_cake)
>
> The "recipe_for_cake" expression is sitting at the top level of
the
> program, where there''s no method_missing defined.  So Ruby
doesn''t
> know what you mean by it.
Good grief -- I''m a space cadet.  I didn''t even notice this
was from
my book, even though you said so in the subject line :-)

So let me add to my answer:

Just before the example, it says:

   Let''s assume there''s a Recipe class, separate from
   the Cookbook class, and we''ve already created some recipe
   objects.

So the idea is that recipe_for_cake and recipe_for_chicken are
instances of Recipe.

To run the example, add this to the beginning:

   class Recipe
   end

   recipe_for_cake = Recipe.new
   recipe_for_chicken = Recipe.new

or just use Object.new and don''t even bother with the Recipe class --
the main thing is to initialize those variables.


David

-- 
http://www.rubypowerandlight.com => Ruby/Rails training & consultancy
   ----> SEE SPECIAL DEAL FOR RUBY/RAILS USERS GROUPS! <-----
http://dablog.rubypal.com        => D[avid ]A[. ]B[lack''s][ Web]log
http://www.manning.com/black     => book, Ruby for Rails
http://www.rubycentral.org       => Ruby Central, Inc.

Dark Ambient

2006-Jul-30 23:44 UTC

head link

[Rails] Method_missing from Ruby for Rails book

David,

I had added the class Recipe and still received same error.
Furthermore, the recipe_for_cake and chicken, are you saying those replace the
cb << recipe_for cake ?
Anyway still no luck here.

Just to show what I have now in code:

class Recipe
end

class Cookbook
  attr_accessor :title, :author

  def initialize
    @recipes = []
  end

  def method_missing(m, *args, &block)
    @recipes.send(m, *args, &block)
  end
end

recipe_for_cake = Recipe.new
recipe_for_chicken = Recipe.new

cb = Cookbook.new
cb << recipe_for_cake
cb << recipe_for_chicken
beef_dishes = cb.find_all {|recipes| recipe.main_ingredient ="beef" }
-----------------------------------------------------------------------------

On 7/30/06, dblack@wobblini.net <dblack@wobblini.net>
wrote:> Hi --
>
> On Sun, 30 Jul 2006, dblack@wobblini.net wrote:
>
> > Hi --
> >
> > On Sun, 30 Jul 2006, Dark Ambient wrote:
> >
> >> I''m having a problem getting this example from the book
to work:
> >>
> >> class Cookbook
> >> attr_accessor :title, :author
> >>
> >> def initialize
> >>   @recipes = []
> >> end
> >>
> >> def method_missing(m, *args, &block)
> >>   @recipes.send(m, *args, &block)
> >> end
> >> end
> >>
> >> cb = Cookbook.new
> >> cb << recipe_for_cake
> >> cb << recipe_for_chicken
> >> beef_dishes = cb.find_all {|recipes| recipe.main_ingredient ==
"beef" }
> >>
> >> I''m getting callable.rb:14: undefined local variable or
method
> >> `recipe_for_cake'' for main:Object (NameError) so
apparently
> >> method_missing is not working.
> >
> > method_missing is working -- it''s just not being called where
you
> > think it is.
> >
> > cb << recipe_for_cake is syntactic sugar for this:
> >
> >  cb.<<(recipe_for_cake)
> >
> > The "recipe_for_cake" expression is sitting at the top level
of the
> > program, where there''s no method_missing defined.  So Ruby
doesn''t
> > know what you mean by it.
>
> Good grief -- I''m a space cadet.  I didn''t even notice
this was from
> my book, even though you said so in the subject line :-)
>
> So let me add to my answer:
>
> Just before the example, it says:
>
>    Let''s assume there''s a Recipe class, separate from
>    the Cookbook class, and we''ve already created some recipe
>    objects.
>
> So the idea is that recipe_for_cake and recipe_for_chicken are
> instances of Recipe.
>
> To run the example, add this to the beginning:
>
>    class Recipe
>    end
>
>    recipe_for_cake = Recipe.new
>    recipe_for_chicken = Recipe.new
>
> or just use Object.new and don''t even bother with the Recipe class
--
> the main thing is to initialize those variables.
>
>
> David
>
> --
> http://www.rubypowerandlight.com => Ruby/Rails training &
consultancy
>    ----> SEE SPECIAL DEAL FOR RUBY/RAILS USERS GROUPS! <-----
> http://dablog.rubypal.com        => D[avid ]A[. ]B[lack''s][
Web]log
> http://www.manning.com/black     => book, Ruby for Rails
> http://www.rubycentral.org       => Ruby Central, Inc.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

dblack@wobblini.net

2006-Jul-30 23:50 UTC

head link

[Rails] Method_missing from Ruby for Rails book

Hi --

On Sun, 30 Jul 2006, Dark Ambient wrote:
> David,
>
> I had added the class Recipe and still received same error.
> Furthermore, the recipe_for_cake and chicken, are you saying those replace 
> the
> cb << recipe_for cake ?
No; what you''ve got is right, except:
> beef_dishes = cb.find_all {|recipes| recipe.main_ingredient =>
"beef" }
Your loop variable is recipes but you''re using recipe (which is
undefined) inside the loop.


David

-- 
http://www.rubypowerandlight.com => Ruby/Rails training & consultancy
   ----> SEE SPECIAL DEAL FOR RUBY/RAILS USERS GROUPS! <-----
http://dablog.rubypal.com        => D[avid ]A[. ]B[lack''s][ Web]log
http://www.manning.com/black     => book, Ruby for Rails
http://www.rubycentral.org       => Ruby Central, Inc.

Dark Ambient

2006-Jul-31 00:02 UTC

head link

[Rails] Method_missing from Ruby for Rails book

David,
I''m lost now .  The variable as recipes should be fine.  recipe is
undefined but I thought the purpose of the code sample was to show how
method_missing still responds to the call. ?
It''s not an easy chapter :) so perhaps I''m missing something.

Stuart

On 7/30/06, dblack@wobblini.net <dblack@wobblini.net>
wrote:> Hi --
>
> On Sun, 30 Jul 2006, Dark Ambient wrote:
>
> > David,
> >
> > I had added the class Recipe and still received same error.
> > Furthermore, the recipe_for_cake and chicken, are you saying those
replace
> > the
> > cb << recipe_for cake ?
>
> No; what you''ve got is right, except:
>
> > beef_dishes = cb.find_all {|recipes| recipe.main_ingredient => >
"beef" }
>
> Your loop variable is recipes but you''re using recipe (which is
> undefined) inside the loop.
>
>
> David
>
> --
> http://www.rubypowerandlight.com => Ruby/Rails training &
consultancy
>    ----> SEE SPECIAL DEAL FOR RUBY/RAILS USERS GROUPS! <-----
> http://dablog.rubypal.com        => D[avid ]A[. ]B[lack''s][
Web]log
> http://www.manning.com/black     => book, Ruby for Rails
> http://www.rubycentral.org       => Ruby Central, Inc.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Tim Haussmann

2006-Jul-31 00:15 UTC

head link

[Rails] form_remote_tag

Hi,
I''m new to ruby and trying to figure out how to get form_remote_tag
working.
I tried two examples. But I''m always ending up with the same behavior.

I want to code a ajax-style search. When the search button is pressed 
the matching rows should be added to the current page. But instead they 
are shown in a new page.

Here follows some more basic code. I''m tried to add the search-string
to
the current page. (Just like the example on 
http://www.onlamp.com/pub/a/onlamp/2005/06/09/rails_ajax.html?page=2). 
The same happens with this, the search-string isn''t added to the
current
page. Instead it''s shown in a new page.


<!--**********
 The list.rhtml:
*************** -->
<%= form_remote_tag(:update =>"search",
                    :url    => {:action => :search}) %>
    <table style="text-align:center;background-color:#dddddd;" 
cellpadding="2" cellspacing="2">
          <tbody>
            <tr>
                  <td style="width: 100px;">Search
for:</td>
                  <td><%= text_field_tag :search_text %></td>
       
                  <td> <%= submit_tag ("Search now")
%></td>
               </tr>
          </tbody>
    </table>   
<%= end_form_tag %>


<ul id="search">
</ul>

<!-- **********************
The search method in the controller:
********** -->
def search
     render_text "<li>" + params[:search_text] +
"</li>"
  end


regards
     tim

dblack@wobblini.net

2006-Jul-31 00:17 UTC

head link

[Rails] Method_missing from Ruby for Rails book

Hi --

On Sun, 30 Jul 2006, Dark Ambient wrote:
> On 7/30/06, dblack@wobblini.net <dblack@wobblini.net> wrote:
>> Hi --
>> 
>> On Sun, 30 Jul 2006, Dark Ambient wrote:
>> 
>> > David,
>> >
>> > I had added the class Recipe and still received same error.
>> > Furthermore, the recipe_for_cake and chicken, are you saying those
>> replace
>> > the
>> > cb << recipe_for cake ?
>> 
>> No; what you''ve got is right, except:
>> 
>> > beef_dishes = cb.find_all {|recipes| recipe.main_ingredient
=>> > "beef" }
>> 
>> Your loop variable is recipes but you''re using recipe (which
is
>> undefined) inside the loop.
>> 
> David,
> I''m lost now .  The variable as recipes should be fine.  recipe is
> undefined but I thought the purpose of the code sample was to show how
> method_missing still responds to the call. ?
> It''s not an easy chapter :) so perhaps I''m missing
something.
something_missing :-)

The thing to remember is that you define method_missing for a
particular class.  So if you do this:

   class Cookbook
     def method_missing(m,*args,&block)
       ...
     end
   end

that doesn''t mean that every unknown identifier anywhere in your
program will be processed by that method.  It means that if you send a
message to a Cookbook object, and the object doesn''t understand the
message, it will send it along to its method_missing.

The ''recipe'' identifier in the block has nothing to do with
any
Cookbook object.  It''s just a misspelled variable name :-)


David

-- 
http://www.rubypowerandlight.com => Ruby/Rails training & consultancy
   ----> SEE SPECIAL DEAL FOR RUBY/RAILS USERS GROUPS! <-----
http://dablog.rubypal.com        => D[avid ]A[. ]B[lack''s][ Web]log
http://www.manning.com/black     => book, Ruby for Rails
http://www.rubycentral.org       => Ruby Central, Inc.

Tim Haussmann

2006-Jul-31 10:42 UTC

head link

[Rails] form_remote_tag

Hi,
I''m new to ruby and trying to figure out how to get form_remote_tag
working.
I tried two examples. But I''m always ending up with the same behavior.

I want to code a ajax-style search. When the search button is pressed
the matching rows should be added to the current page. But instead they
are shown in a new page.

Here follows some more basic code. I tried to add the search-string to
the current page. (Just like the example on
http://www.onlamp.com/pub/a/onlamp/2005/06/09/rails_ajax.html?page=2).
The same happens with this, the search-string isn''t added to the
current
page. Instead it''s shown in a new page.


<!--**********
The list.rhtml:
*************** -->
<%= form_remote_tag(:update =>"search",
                    :url    => {:action => :search}) %>
    <table style="text-align:center;background-color:#dddddd;"
cellpadding="2" cellspacing="2">
          <tbody>
            <tr>
                  <td style="width: 100px;">Search
for:</td>
                  <td><%= text_field_tag :search_text %></td>

                  <td> <%= submit_tag ("Search now")
%></td>
               </tr>
          </tbody>
    </table>
<%= end_form_tag %>


<ul id="search">
</ul>

<!-- **********************
The search method in the controller:
********** -->
def search
     render_text "<li>" + params[:search_text] +
"</li>"
  end


regards
     tim

_______________________________________________
Rails mailing list
Rails@lists.rubyonrails.org
http://lists.rubyonrails.org/mailman/listinfo/rails

Reasonably Related Threads

Search for more maybe matching threads

Rails - Jul 2006 - Method_missing from Ruby for Rails book

[Rails] Method_missing from Ruby for Rails book

[Rails] Method_missing from Ruby for Rails book

[Rails] Method_missing from Ruby for Rails book

[Rails] Method_missing from Ruby for Rails book

[Rails] Method_missing from Ruby for Rails book

[Rails] Method_missing from Ruby for Rails book

[Rails] form_remote_tag

[Rails] Method_missing from Ruby for Rails book

[Rails] form_remote_tag

Reasonably Related Threads