--- a/streamlet-examples/xpath.cpp	Wed Jan 29 18:41:42 2020 +0100
+++ b/streamlet-examples/xpath.cpp	Wed Jan 29 20:50:12 2020 +0100
@@ -21,6 +21,27 @@
 #include <regex>
 #include <libxml++-2.6/libxml++/libxml++.h>
 
+/**
+ * This streamlet provides values from XML files.
+ * It uses the XPath language to define, what portion of XML should be returned.
+ * 
+ * With no options it does not provide any attributes.
+ * 
+ * XPath expressions are passed as 'attribute' options.
+ * e.g. --option 'attribute' 'name()' will return single attribute with the name of the root node.
+ * 
+ * Attributes can be renamed using aliases: --option 'attribute' 'name()' --as 'name'. Otherwise the full XPath expression is used as a name.
+ * Number of aliases should match the number of attributes (otherwise only first attributes are renamed, because aliases are global, not relative to the --option).
+ * 
+ * Like relpipe-in-xmltable, this streamlet supports several modes:
+ *  - string
+ *  - boolean
+ *  - raw-xml
+ *  - line-number
+ *  - xpath
+ * 
+ * TODO: more OOP, move to separate repository, proper CMake project, clean-up, stabilize API
+ */
 class XPathStreamlet : public Streamlet {
 private:
 	xmlpp::Node::PrefixNsMap ns;