Added a note about the lacking features of Yaml Component

Author: javiereguiluz

components/yaml/introduction.rst

@@ -2,24 +2,24 @@
    single: Yaml
    single: Components; Yaml
 
-The YAML Component
+The Yaml Component
 ==================
 
-    The YAML Component loads and dumps YAML files.
+    The Yaml Component loads and dumps YAML files.
 
 What is It?
 -----------
 
-The Symfony2 YAML Component parses YAML strings to convert them to PHP arrays.
+The Symfony2 Yaml Component parses YAML strings to convert them to PHP arrays.
 It is also able to convert PHP arrays to YAML strings.
 
 `YAML`_, *YAML Ain't Markup Language*, is a human friendly data serialization
 standard for all programming languages. YAML is a great format for your
 configuration files. YAML files are as expressive as XML files and as readable
 as INI files.
 
-The Symfony2 YAML Component implements the YAML 1.2 version of the
-specification.
+The Symfony2 Yaml Component implements a selected subset of features defined in
+the `YAML 1.2 version specification`_.
 
 .. tip::
 
@@ -40,8 +40,10 @@ Why?
 Fast
 ~~~~
 
-One of the goal of Symfony YAML is to find the right balance between speed and
-features. It supports just the needed feature to handle configuration files.
+One of the goals of Symfony Yaml is to find the right balance between speed and
+features. It supports just the needed features to handle configuration files.
+Notable lacking features are: document directives, multi-line quoted messages,
+compact block collections and multi-document files.
 
 Real Parser
 ~~~~~~~~~~~
@@ -78,7 +80,7 @@ yourself by referencing common configuration bits.
 Using the Symfony2 YAML Component
 ---------------------------------
 
-The Symfony2 YAML Component is very simple and consists of two main classes:
+The Symfony2 Yaml Component is very simple and consists of two main classes:
 one parses YAML strings (:class:`Symfony\\Component\\Yaml\\Parser`), and the
 other dumps a PHP array to a YAML string
 (:class:`Symfony\\Component\\Yaml\\Dumper`).
@@ -163,7 +165,7 @@ array to its YAML representation:
 
 .. note::
 
-    Of course, the Symfony2 YAML dumper is not able to dump resources. Also,
+    Of course, the Symfony2 Yaml dumper is not able to dump resources. Also,
     even if the dumper is able to dump PHP objects, it is considered to be a
     not supported feature.
 
@@ -213,3 +215,4 @@ representation to the inline one:
 
 .. _YAML: http://yaml.org/
 .. _Packagist: https://packagist.org/packages/symfony/yaml
+.. _`YAML 1.2 version specification`: http://yaml.org/spec/1.2/spec.html