Trying to create a "view object" with yield self

[Pry Flack]

Hi I'm having a problem creating a view widget inside my erb template.

Please see the following gist https://gist.github.com/5723324

Basically I'm trying to isolate a complex piece of html markup with
something like :

<%= Accordion.new(parent: "my-parent") do |accordion| %>
accordion.element("elem1")
accordion.element("elem2")
<% end %>

But yielding self does not return my object instance but the erb
template. It seems in rails there is a need to "capture" a given block
but I can't figure out how to do this. I'm able to do something similar
via a rails helper however I wanted to create an object to keep things
DRY. Any help much appreciated !

--
Posted via http://www.ruby-forum.com/.

[Pry Flack]

Berlimioz wrote in post #1111637:
> Hi pry_f !
>
> Sorry but I'm not sure to have exactly understood what you're trying to
> do.
> What I understand from the code you made available is that the lines
> below
> should display something like
>
> <p>opening</p>
> <li> elem1: parent is my-parent</li>
> <li> elem2: parent is my-parent</li>
> <p>closing</p>
>
> and it doesn't ?
>
> Le jeudi 6 juin 2013 19:48:46 UTC+2, Ruby-Forum.com User a crit :

That's right. This is not a model related problem. I'm trying
to make view "widgets" basically.
I created another gist. This time it's just a ruby script demonstrating
the concept by printing to standard out.
https://gist.github.com/PryFlack/5732422

I have a little bug as mentioned in the comment. I was pretty sure this
was going to work in plain ruby. Anyways with rails I've had trouble
implementing this idea even more. I don't see how I could use partials
for that so the only thing I can think of is what I'm doing here. Thanks
for your feedback and interest !

[Berlimioz]

Ok, maybe this could help :

When your method initialize returns a string, calling Accordion.new doesn't return this string, because the initialize method is called in the new method, but that's not what's returned by the new class method. 

On the other hand, when you have this :

<<-EOF
      <div class="accordion" id="#{@parent_id}"> <!-- first line -->
        #{yield self}
      </div> <!-- last line -->
    EOF

the expression "yield self" will here return the return value of the block you pass. When you pass a block like this : 

Accordion.new() do |accordion|

  "something here"

  "something there"

end

the return value of the block is only "something there" (last line of the block). So that 

<<-EOF

<div class="accordion" id="#{@parent_id}"> <!-- first line -->

#{yield self}

</div> <!-- last line -->

EOF

will actually results in something like :

<div class="accordion" id="#{@parent_id}"> <!-- first line -->

something there

</div> <!-- last line -->

Hope it helped, enjoy your week end anyway !

[Pry Flack]

Berlimioz wrote in post #1111694:

> On the other hand, when you have this :
>
> <<-EOF
> <div class="accordion" id="#{@parent_id}"> <!-- first line -->
> #{yield self}
> </div> <!-- last line -->
> EOF
>
> the expression "yield self" will here return the return value of the
> block
> you pass. When you pass a block like this :

Yes that's what I was trying to do. I found my mystake. I need to use an
instance variable to build the output buffer. Here is a working ruby
"prototype" https://gist.github.com/PryFlack/5732422

Now I'm gonna have to bring this into my rails app and see how it goes
because as I said yield self behaves differently inside an ERB template.

Enjoy your week-end too !

[Pry Flack]

Pry Flack wrote in post #1111699:

Well I am failing miserably with this!

My latest attempt here: https://gist.github.com/PryFlack/5723324

Having so much difficulty with this I thought about going a different
way. I realized i could also do the following:

=====START=====
<% parent_id = "myAccordion" %>

<%= render layout: 'accordion', locals: { parent_id: parent_id }
do |parent| %>

<%= render layout: 'accordion_element',
locals: { target_id: "collapseRow1", title: "Row1",
parent_id: parent_id, in_or_out: "in" } do %>

<p>inside child1</p>
<% end %>

<%= render layout: 'accordion_element',
locals: { target_id: "collapseRow2", title: "Row2",
parent_id: parent_id, in_or_out: nil } do %>

<p>inside child2</p>
<% end %>

<% end %>
=====END=====

However this is still pretty verbose. So this adds more complexity and
it's pretty rigid (if I want to modify the rendering of the html
block, I have to modify my calls to render everywhere)

Also apart from creating an instance variable inside the erb template, I
don't see a good way to pass value in the nested rendered layout (other
than repeating myself)

Has anybody got any good info on how to generate and abstract complex
html blocks ?