Add simple support for tags in YAML I/O

[oota-llvm.git] / docs / YamlIO.rst

diff --git a/docs/YamlIO.rst b/docs/YamlIO.rst
index 79e07cd98977a68a5e3e0f0fad96168213cfc248..3ecd03afb24d8871d2dd51f085cfa9806ff865bc 100644 (file)
--- a/docs/YamlIO.rst
+++ b/docs/YamlIO.rst
@@ -633,6 +633,20 @@ This works for both reading and writing. For example:
     };
 
 
+Tags
+----
+
+The YAML syntax supports tags as a way to specify the type of a node before
+it is parsed. This allows dynamic types of nodes.  But the YAML I/O model uses
+static typing, so there are limits to how you can use tags with the YAML I/O
+model. Recently, we added support to YAML I/O for checking/setting the optional 
+tag on a map. Using this functionality it is even possbile to support differnt 
+mappings, as long as they are convertable.  
+
+To check a tag, inside your mapping() method you can use io.mapTag() to specify
+what the tag should be.  This will also add that tag when writing yaml.
+
+
 Sequence
 ========