#40 Blocks in View

Good example!
I google about "Variable Bindings in Ruby"
http://onestepback.org/index.cgi/Tech/Ruby/RubyBindings.rdoc
and,with your example,I understand it
tks!

Wildly useful and solves a small problem I had with my views. Thanks, Ryan!

I have just one small suggestion.

When you have Ruby wrap the block into an object for you (by adding a &block parameter), I think it's more consistent to use block.call over yield. Generally I thin you either want to go with a yield/block_given? strategy or a &block/block.call/block.nil? strategy, depending on the method you are writing. But it's probably best not to mix and match. In your examples, we need the block object to get the binding, so the latter is better.

GOOD!!!!!

@JEG2, thanks for the suggestion. I've seen the mix of yield and &block in other places as well (such as the source of fields_for) which is one reason I didn't think it mattered. But you know Ruby probably better than any of us here, so I'll try to stick with your suggestion. Thanks! :)

Excellent tips, I'll have to implement this soon. One question though...how does the use of blocks in the views work with caching? Does it at all or are there some limitations? Thanks, great screencasts. I look forward to the new ones all the time.

I don't think there's any issues with caching. You just have to watch out for setting instance variables (like the side sections example). If you cache outside the block, the helper method won't be called every time and the instance variable won't be set.

How do you do something like yield(msg) in actionview?

@Brian, you should be able to do that without any issues (just like any normal yield call). Is it not working?

Well I mean it does but I want to surround it with tags. ie create div or a ul and then insert the yield(msg) result in it. No point in creating the ul or div if there's nothing to go in it. Do you have the site notify you when comments are posted cause that was ridiculously fast.

Hmm, not entirely sure what you're asking, but eithe way it should work without any changes. See this pastie code for an example of passing a string to the block.

http://pastie.caboo.se/84044

Sweet. That's exactly what I needed I didn't know you could pass an argument to capture

to weskycn:
Don't say anything not related to the topic. obeying the rule is the most polite than words,okey?
actually,I am a chinese too.
-------
blocks in view is powerful,especially with "capture"'s help.
I finished a "table_for" helper with the mechinism,the usage like this:
<% table_for :users do |t|
     t.column :full_name {|user| h user.first_name + " " + user.last_name}
     t.columns :age,:birthday
     t.columns :$edit,:$show
%>

<% t.erb_column('Destroy') do |user| %>
<% if user.name != 'xxx' %>
  <%= link_to 'Destroy',user_path(user),:method=>:delete %>
<% end %>
<% end
     end
%>

some features like "pagination","odd-even style","column sortable with correct sort-type" supported,and we can imagine more features like "export to excel","Globalization" to be added to "table_for" helper. so only open some options like :sortable=>false,we keep the code clean,consistent and maintainable. (like j2ee's displaytag?)

for it's used in my company,I am sorry not able to share the code to public.

let's enjoy blocks in view :)

Sorry... completely off topic.

If you listen very very closely you can hear frogs in the background. I can't help but imagine that you live on a bijou ala Happy Gilmore or something busting out awesome rails nuggets of smart from your two room shack.

Is it possible to do something like:

<% my_box do |box| %>
  <% box.head do %>
     ...
  <% end %>
  <% box.content do %>
     ...
  <% end %>
<% end %>

As you see its going to wrap some HTML for a rounded box.

I tried for several hours to find a solution. The main problem is that i cant capture the contents of the block.call(some_function) method. It always outputs everything to the template immediatly.

Is there a way to it?

As in the comment from "space" mentioned, it's a bit complicated to build helper method for multiple wrapped tags. I found, that with HAML this task is very simple, because you get the helper methods "open" and "puts".

I have written a blog entry about this:
http://www.dipl-wirt-inf.de/2008/02/17/elegante-block-helper-mit-haml/

(german language, but you will get point with the code examples).

This was a really useful episode, ROR really is awesome in that it lets you write code like that!

Love your screencasts, learn something new everytime! Thanks

Thanks and i will bookmark your sitee

Useful but maybe a revised version could be awesome

I'd also like to see an update, as I think the block/yield behaviour changed a lot since the video?

-- http://railscasts.com/episodes/208-erb-blocks-in-rails-3?view=asciicast

This episode has been updated for Rails 5 as a blog post. Blocks in View