module ActionView # = Action View Layouts module Layouts # 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 # # <%= yield %> # # # 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 # # # Content # # # 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 # # <%= yield Struct.new(:name).new("David") %> # # # 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 # # # Hello David # # def _layout_for(name = nil, &block) #:nodoc: if !block || name @_content_for[name || :layout].html_safe else capture(&block) end end # This is the method which actually finds the layout using details in the lookup # context object. If no layout is found, it checks if at least a layout with # the given name exists across all details before raising the error. def find_layout(layout) begin with_layout_format do layout =~ /^\// ? with_fallbacks { find_template(layout) } : find_template(layout) end rescue ActionView::MissingTemplate => e update_details(:formats => nil) do raise unless template_exists?(layout) end end end # Contains the logic that actually renders the layout. def _render_layout(layout, locals, &block) #:nodoc: layout.render(self, locals){ |*name| _layout_for(*name, &block) } end end end