Improve capture helper documentation. Closes #8796.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7148 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

Improve capture helper documentation. Closes #8796.
git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7148 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
dfc15e12 · Jeremy Kemper · f26141c9 · dfc15e12 · dfc15e12
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actionpack/CHANGELOG actionpack/CHANGELOG +2 -0

actionpack/lib/action_view/helpers/capture_helper.rb actionpack/lib/action_view/helpers/capture_helper.rb +41 -25

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--- a/actionpack/CHANGELOG
+++ b/actionpack/CHANGELOG
 *SVN*

+* Improve capture helper documentation.  #8796 [kampers]
+
 * Prefix nested resource named routes with their action name, e.g. new_group_user_path(@group) instead of group_new_user_path(@group). The old nested action named route is deprecated in Rails 1.2.4.  #8558 [David Chelimsky]

 * Allow sweepers to be created solely for expiring after controller actions, not model changes [DHH]

--- a/actionpack/lib/action_view/helpers/capture_helper.rb
+++ b/actionpack/lib/action_view/helpers/capture_helper.rb
@@ -3,10 +3,10 @@ module Helpers
    # CaptureHelper exposes methods to let you extract generated markup which
    # can be used in other parts of a template or layout file.
    # It provides a method to capture blocks into variables through capture and 
-    # a way to capture a block of code for use in a layout through content_for.
+    # a way to capture a block of markup for use in a layout through content_for.
    module CaptureHelper
-      # The capture method allows you to extract a part of the template into a 
-      # variable. You can then use this value anywhere in your templates or layout. 
+      # The capture method allows you to extract part of a template into a 
+      # variable. You can then use this variable anywhere in your templates or layout. 
      # 
      # ==== Examples
      # The capture method can be used in RHTML (ERb) templates...
@@ -22,8 +22,7 @@ module CaptureHelper
      #     "The current timestamp is #{Time.now}."
      #   end
      #
-      # You can then use the content as a variable anywhere else.  For
-      # example:
+      # You can then use that variable anywhere else.  For example:
      #
      #   <html>
      #   <head><title><%= @greeting %></title></head>
@@ -46,21 +45,21 @@ def capture(*args, &block)
        end
      end
      
-      # Calling content_for stores the block of markup in an identifier for later use.
-      # You can make subsequent calls to the stored content in another template or in the layout
-      # by calling it by name with <tt>yield</tt>.
+      # Calling content_for stores a block of markup in an identifier for later use.
+      # You can make subsequent calls to the stored content in other templates or the layout
+      # by passing the identifier as an argument to <tt>yield</tt>.
      # 
      # ==== Examples
      # 
-      #   <% content_for("authorized") do %>
-      #     alert('You are not authorized for that!')
+      #   <% content_for :not_authorized do %>
+      #     alert('You are not authorized to do that!')
      #   <% end %>
      #
-      # You can then use <tt>yield :authorized</tt> anywhere in your templates.
+      # You can then use <tt>yield :not_authorized</tt> anywhere in your templates.
      #
-      #   <%= yield :authorized if current_user == nil %>
+      #   <%= yield :not_authorized if current_user.nil? %>
      #
-      # You can also use these variables in a layout.  For example:
+      # You can also use this syntax alongside an existing call to <tt>yield</tt> in a layout.  For example:
      #
      #   <!-- This is the layout -->
      #   <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
@@ -73,33 +72,50 @@ def capture(*args, &block)
      #   </body>
      #   </html>
      #
-      # And now we'll create a view that has a content_for call that
+      # And now, we'll create a view that has a content_for call that
      # creates the <tt>script</tt> identifier.
      #
      #   <!-- This is our view -->
      #   Please login!
      #
-      #   <% content_for("script") do %>
-      #     <script type="text/javascript">alert('You are not authorized for this action!')</script>
+      #   <% content_for :script do %>
+      #     <script type="text/javascript">alert('You are not authorized to view this page!')</script>
      #   <% end %>
      #
-      # Then in another view you may want to do something like this:
+      # Then, in another view, you could to do something like this:
      #
      #   <%= link_to_remote 'Logout', :action => 'logout' %>
      #
-      #   <% content_for("script") do %>
+      #   <% content_for :script do %>
      #     <%= javascript_include_tag :defaults %>
      #   <% end %>
      #
-      # That will include Prototype and Scriptaculous into the page; this technique
-      # is useful if you'll only be using these scripts on a few views.
+      # That will place <script> tags for Prototype, Scriptaculous, and application.js (if it exists)
+      # on the page; this technique is useful if you'll only be using these scripts in a few views.
      #
-      # NOTE: Beware that content_for is ignored in caches. So you shouldn't use it
-      # for elements that are going to be fragment cached.
+      # Also, note that content_for concatenates the blocks it is given for a particular
+      # identifier in order. For example:
      #
-      # The deprecated way of accessing a content_for block was to use a instance variable
-      # named @@content_for_#{name_of_the_content_block}@. So <tt><%= content_for('footer') %></tt>
-      # would be avaiable as <tt><%= @content_for_footer %></tt>. The preferred notation now is
+      #   <% content_for :navigation do %>
+      #     <li><%= link_to 'Home', :action => 'index' %></li>
+      #   <% end %>
+      #
+      #   <!-- Add some other content, or use a different template: -->
+      # 
+      #   <% content_for :navigation do %>
+      #     <li><%= link_to 'Login', :action => 'login' %></li>
+      #   <% end %>
+      #
+      # Then, in another template or layout, this code would render both links in order:
+      #
+      #   <ul><%= yield :navigation %></ul>
+      #      
+      # WARNING: content_for is ignored in caches. So you shouldn't use it
+      # for elements that will be fragment cached.
+      #
+      # The deprecated way of accessing a content_for block is to use an instance variable
+      # named <tt>@content_for_#{name_of_the_content_block}</tt>. So <tt><%= content_for :footer %></tt>
+      # would be avaiable as <tt><%= @content_for_footer %></tt>. The preferred usage is now
      # <tt><%= yield :footer %></tt>.
      def content_for(name, content = nil, &block)
        eval "@content_for_#{name} = (@content_for_#{name} || '') + capture(&block)"