# ContentFor
Small extension for the [Sinatra](http://sinatrarb.com) web framework
that allows you to use the following helpers in your views:
<% content_for :some_key do %>
yield_content
is called without
an '=' block (<%= %>
), but with Haml it uses = yield\_content
.
Using an '=' block in ERB will output the content twice for each block,
so if you have problems with that, make sure to check for this.
## Usage
If you're writing "classic" style apps, then requring
sinatra/content_for
should be enough. If you're writing
"classy" apps, then you also need to call
helpers Sinatra::ContentFor
in your app definition.
## And how is this useful?
For example, some of your views might need a few javascript tags and
stylesheets, but you don't want to force this files in all your pages.
Then you can put <% yield\_content :scripts\_and\_styles %>
on
your layout, inside the
content_for
setting the appropriate set of tags that should
be added to the layout.
## How is this different from [foca](http://github.com/foca)'s version?
This code was based on [foca's version](http://github.com/foca), which supports passing block values to the content, which means lazy rendering of the blocks. This plays havoc with anything that assumes that views are rendered before layouts, such as setting instance variables and the [fancyviews](http://github.com/quackingduck/fancyviews) plugin.
## Credits
Original code by [foca](http://github.com/foca), inspired on the Ruby on Rails helpers with the same name. Haml support by [macodely](http://github.com/macodely). Modified by me (Tim Lucas) for the above reasons.