Add ls

Change-Id: I86f799ff9577940c7df8e01cda6c6b7867de8e7e
diff --git a/src/parser.cpp b/src/parser.cpp
index ac3ba84..0eb94fd 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -53,3 +53,11 @@
 {
     return pathToDataString(m_curDir);
 }
+
+std::set<std::string> Parser::availableNodes(const boost::optional<path_>& path) const
+{
+    auto pathArg = m_curDir;
+    if (path)
+        pathArg.m_nodes.insert(pathArg.m_nodes.end(), path->m_nodes.begin(), path->m_nodes.end());
+    return m_schema->childNodes(pathArg);
+}