Agile Web Development Book, need a bit of help

rubyonrails-talk
1

collection.each do |object|    object.stuff end

is equivalent to

for object in collection    object.stuff end

Just try having collection be something that doesn't respond_to "each" and see the error that the 'for' version gives you.

(I know that I'm not really answering the OP's question about the cart or the BigDecimal error, but the suggestion in the first response isn't valid or even syntactically correct.)

-Rob

Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com

2

In a view perhaps?

<% if @items -%>    <ul>      <% @items.each do |item| -%>        <li><%= item %></li>      <% end -%>    </ul> <% else -%>    <p>Sorry, no items</p> <% end -%>

You could say 'unless @items.blank?' in place of 'if @items' with the same result.

-Rob

Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com

3

I found if I changed the code to this:

<h1>Display Cart</h1> <table>

<thead> <tr><th>Title</th></tr> </thead> <tbody>

<% for item in @items %>

<% for item in @cart.items %>

<%= item%>

<tr><td><%= item.title %></td></tr>

<% end %>

</tbody>

</table>

It printed out just the price field from the database, which makes me think perhaps something is wrong with my model?

Here's my table: id title description image_url price date_available

Here's my model:

class Cart   attr_reader :items   attr_reader :total_price

  def initialize   @items =   @total_price = 0.0   end

  def add_product(product)     @items << LineItem.for_product(product)     @total_price += product.price   end end

Thanks for the help.

Mark --

Without seeing what you're doing in the controller, that's all I can say.

-Rob

Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com

4

So does the view work now? You can also have: <%= item.inspect %>

to find out what item is (if it's nil, nil.inspect => "nil")

-Rob

Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com

5

Good point. Using debug() also puts some nice CSS classes on the output so you can format it (like display:none;) and still get to it in the "view source" or by changing the CSS dynamically (Firebug or alternate stylesheets)

-Rob

Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com

6

That's the class into which database floats and decimal values are reified. It is a class that retains decimal places accurately (something that is simply not possible with binary-encoded approximations to real decimal numbers).

-Rob

Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com