README file

README.md

@@ -1,2 +1,15 @@
 SaXPath
 =======
+Simple XPath evaluator which runs against a SAX stream.
+
+Supported XPath construct as of writing are:
+  - '/'-axis (child)
+  - '//'-axis (self-or-descendant)
+  - node name tests
+  - predicate test (@<attribute_name> = "<literal>")
+
+Inner workings
+--------------
+A state machine is built which the SAX-nodes are tested against. If a node matches, the state machine progresses.
+
+For self-or-descendant-nodes, the state machine is forked and earch fork (including the parent) is tested against the SAX-nodes. This ensures all nodes are matched. See test/saxpath.js and test/inception.xml for an example.