Overwrites _layout_for in the context object so it supports the case a block is passed to a partial. Returns the contents that are yielded to a layout, given a name or a block.
You can think of a layout as a method that is called with a block. If the user calls yield :some_name, the block, by default, returns content_for(:some_name). If the user calls simply yield, the default block returns content_for(:layout).
The user can override this default by passing a block to the layout:
# The template <%= render layout: "my_layout" do %> Content <% end %> # The layout <html> <%= yield %> </html>
In this case, instead of the default block, which would return content_for(:layout), this method returns the block that was passed in to render :layout, and the response would be
<html> Content </html>
Finally, the block can take block arguments, which can be passed in by yield:
# The template <%= render layout: "my_layout" do |customer| %> Hello <%= customer.name %> <% end %> # The layout <html> <%= yield Struct.new(:name).new("David") %> </html>
In this case, the layout would receive the block passed into render :layout, and the struct specified would be passed into the block as an argument. The result would be
<html> Hello David </html>
# File actionpack/lib/action_view/helpers/rendering_helper.rb, line 79 def _layout_for(*args, &block) name = args.first if block && !name.is_a?(Symbol) capture(*args, &block) else super end end