Block usage of content_tag

rubyonrails-talk
1

Arnaud take a look at the Rails source for content_tag: http://pastie.caboo.se/80983

      def content_tag(name, content_or_options_with_block = nil, options = nil, &block)         if block_given?           options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)           content = capture(&block)           concat(content_tag_string(name, content, options), block.binding)         else           content = content_or_options_with_block           content_tag_string(name, content, options)         end       end

If you give it a block, it calls concat(content_tag_string(name, content, options), block.binding).

module StoreHelper

  def hidden_div_if(condition, attributes = {})     if condition       attributes["style" ] = "display: none"     end     content_tag("div" , attributes) {yield}   end

...

If you use content_tag("div" , attributes) {yield} inside your hidden_div_if(), when concat inside content_tag() will be called w/ the binding of you block: {yield}, which has the StoreHelper's context as to your View's context: (the original block passed in hidden_div_if). As a result, when concat() gets called inside content_tag, it doesn't have the right binding and hence missing: "_erbout." I hope this helps. :slight_smile:

2

David Dai wrote:

Arnaud take a look at the Rails source for content_tag: Parked at Loopia

     def content_tag(name, content_or_options_with_block = nil, options = nil, &block)        if block_given?          options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)          content = capture(&block)          concat(content_tag_string(name, content, options), block.binding)        else          content = content_or_options_with_block          content_tag_string(name, content, options)        end      end

If you give it a block, it calls concat(content_tag_string(name, content, options), block.binding).

module StoreHelper

  def hidden_div_if(condition, attributes = {})     if condition       attributes["style" ] = "display: none"     end     content_tag("div" , attributes) {yield}   end

...

If you use content_tag("div" , attributes) {yield} inside your hidden_div_if(), when concat inside content_tag() will be called w/ the binding of you block: {yield}, which has the StoreHelper's context as to your View's context: (the original block passed in hidden_div_if). As a result, when concat() gets called inside content_tag, it doesn't have the right binding and hence missing: "_erbout." I hope this helps. :slight_smile:

Thanks - that confirms what I implied, when I was too lazy to look up the actual method!

The best way to use capture{} is don't, guys! (-;