Update README.md

README.md

@@ -4,7 +4,7 @@ RABL (Ruby API Builder Language) is a ruby templating system for rendering resou
 
 RABL-rails only target Rails 3+ application because Rails 2 applications are becoming less and less present and will be obsolete with Rails 4. So let's look to the future !
 
-So now you ask why used `rabl-rails` if `rabl` already exists and supports Rails. Rabl-rails is *faster* and uses * less memory* than standard rabl gem while letting you access same features. Of course, there are some slight changes to do on your templates to get this gem to work but it should't take you more than 5 minutes.
+So now you ask why used `rabl-rails` if `rabl` already exists and supports Rails. Rabl-rails is **faster** and uses **less memory** than standard rabl gem while letting you access same features. Of course, there are some slight changes to do on your templates to get this gem to work but it should't take you more than 5 minutes.
 
 ## Installation
 
@@ -17,7 +17,7 @@ gem install rabl-rails
 or add directly to your `Gemfile`
 
 ```
-gem 'rabl'
+gem 'rabl-rails'
 ```
 
 And that's it !
@@ -30,9 +30,9 @@ assuming you have a `Post` model filled with blog posts, and a `PostController`
 ```ruby
 class PostController < ApplicationController
 	respond_to :html, :json, :xml
-	
+
 	def index
-		@posts = Post.order('created_at DESC')
+	@posts = Post.order('created_at DESC')
 		respond_with(@posts)
 	end
 end
@@ -64,7 +64,7 @@ That's a basic overview but there is a lot more to see such as partials, inherit
 
 As opposed to standard RABL gem, this gem separate compiling (a.k.a transforming a RABL-rails template into a Ruby hash) and the actual rendering of the object or collection. This allow to only compile the template once and only Ruby hashes.
 
-The fact of compiling the template outside of any rendering context prevent us to use any instances variables (with the exception of node) in the template because they are rendering objects. So instead, you'll have to use symbols of these variables. For example, to render the collection `@posts` inside your `PostController`, you need to use `:@posts` inside of the template.
+The fact of compiling the template outside of any rendering context prevent us to use any instances variables (with the exception of node) in the template because they are rendering objects. So instead, you'll have to use symbols of these variables.For example, to render the collection `@posts` inside your `PostController`, you need to use `:@posts` inside of the template.
 
 The only places where you can actually used instance variables  are into Proc (or lambda) or into custom node (because they are treated as Proc).
 
@@ -81,4 +81,169 @@ The same rule applies for view helpers such as `current_user`
 
 After the template is compiled into a hash, Rabl-rails will use a renderer to do the actual output. Actually, only JSON and XML formats are supported.
 
-## Usage
+## Usage
+
+### Data declaration
+
+To declare data to use in the template, you can use either `object` or `collection` with the symbol name or your data.
+
+```ruby
+# app/views/users/show.json.rabl
+object :@user
+
+# app/views/users/index.json.rabl
+collection :@users
+```
+
+You can specify root label for the collection using hash or `:root` option
+
+```ruby
+	collection :@posts, root: :articles
+	#is equivalent to
+	collection :@posts => :articles
+
+	# => { "articles" : [{...}, {...}] }
+```
+
+There are rares cases when the template doesn't map directly to any object. In these cases, you can set data to false or skip data declaration altogether.
+
+```ruby
+	object false
+	node(:some_count) { |_| @user.posts.count }
+	child(:@user) { attribute :name }
+```
+
+### Attributes / Methods
+
+Basic usage is to declared attributes to include in the response. These can be database attributes or any instance method.
+
+```ruby
+	attributes :id, :title, :to_s
+```
+
+You can aliases these attributes in your response
+
+```ruby
+	attributes title: :foo, to_s: :bar
+	# => { "foo" : <title value>, "bar" : <to_s value> } 
+```
+
+### Child nodes
+
+You can include nested information from data associated with the parent model. You can also alias these associations.
+For example if you have a `Post` model that belongs to a `User`
+
+```ruby
+	object :@post
+	child(user: :author) do
+		attributes :name
+	end
+	# => { "post" : { "author" : { "name" : "John D." } } }
+```
+
+You can also use arbitrary data source with child nodes
+```ruby
+	child(:@users) do
+		attributes :id, :name
+	end
+```
+
+### Custom nodes
+
+You can create custom node in your response, based on the result of the given block
+
+```ruby
+	object :@user
+	node(:full_name) { |u| u.first_name + " " + u.last_name }
+	# => { "user" : { "full_name" : "John Doe" } }
+```
+
+You can add the node only if a condition is true
+
+```ruby
+	node(:email, if: -> { |u| u.valid_email? }) do |u| 
+		u.email
+	end
+```
+
+Nodes are evaluated at the rendering time, so you can use any instance variables or view helpers inside them
+
+```ruby
+	node(:url) { |post| post_url(post) }
+```
+
+Custom nodes are really usefull to create flexible representations of your resources.
+
+### Extends & Partials
+
+Often objects have a basic representation that is shared accross different views and enriched according to it. To avoid code redundancy you can extend your template from any other RABL template.
+
+```ruby
+# app/views/users/base.json.rabl
+attributes :id, :name
+
+# app/views/users/private.json.rabl
+extends 'users/base'
+attributes :super_secret_attribute
+```
+
+You can also extends template in child nodes using `partial` option (this is the same as using `extends` in the child block)
+
+```ruby
+collection @posts
+attribute :title
+child(:user, partial: 'users/base')
+```
+
+Partials can also be used inside custom nodes. When using partial this way, you MUST declare the object associated to the partial
+
+```ruby
+node(:location) do |user|
+	{ city: user.city, address: partial('users/address', object: m.address) }
+end
+```
+
+### Nesting
+
+Rabl allow you to define easily your templates, even with hierarchy of 2 or 3 levels. Let's suppose your have a `thread` model that has many `posts` and that each post has many `comments`. We can display a full thread in a few lines
+
+```ruby
+	object :@thread
+	attribute :caption
+	child :posts do
+		attribute :title
+		child :comments do
+			extends 'comments/base'
+		end
+	end
+```
+
+## Performance
+
+Performance tests have been made using this [application](http://github.com/ccocchi/rabl-benchmark), with Rabl 0.9 and Rabl-rails 0.2.0
+
+Overall, Rabl-rails is **20% faster and use 15% less memory**.
+
+You can see full tests and graphic on the benchmark application repository.
+
+## Caching
+
+Caching is not a part of Rabl-rails. It is already in Rails itself, because caching all view output is the same as action caching (Rails caching is even better because it will also not run your queries).
+
+And caching each object in a collection can be really not effective with big collections or simple objects. This is also a nightmare with cache expiration.
+
+## Resources
+
+## Authors and contributors
+
+* [Christopher Cocchi-Perrier](http://github.com/ccocchi) - Creator of the project
+
+Want to add another format to Rabl-rails ? Checkout [JSON renderer](http://github.com/ccocchi/rabl-rails/blob/master/lib/rabl-rails/renderers/json.rb) for reference
+
+Want to make another change ? Just fork and contribute, any help is very much appreciated
+
+## Original idea
+
+* [RABL](http://github.com/nesquena/rabl) Standart RABL gem is used a lot before deciding I wanted faster views
+
+## Copyright