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