Add some doc to the extractor

extractor/extraction_way.hpp

@@ -34,6 +34,12 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <string>
 #include <vector>
 
+/**
+ * This struct is the direct result of the call to ```way_function```
+ * in the lua based profile.
+ *
+ * It is split into multiple edge segments in the ExtractorCallback.
+ */
 struct ExtractionWay
 {
     ExtractionWay() { clear(); }

extractor/extractor_callbacks.cpp

@@ -72,7 +72,15 @@ void ExtractorCallbacks::ProcessRestriction(
         //                           "y" : "n");
     }
 }
-/** warning: caller needs to take care of synchronization! */
+/**
+ * This function takes the geometry contained in the ```input_way``` and the tags
+ * computed by the lua profile inside ```parsed_way``` and computes all edge segments.
+ *
+ * Depending on the forward/backwards weights the edges are split into forward and backward
+ * edges.
+ *
+ * warning: caller needs to take care of synchronization!
+ */
 void ExtractorCallbacks::ProcessWay(const osmium::Way &input_way, const ExtractionWay &parsed_way)
 {
     if (((0 >= parsed_way.forward_speed) ||