Making the turn function more flexible (#4789)

* set and store highway and access classification for the turn function
* expose highway turn classification and access turn classification and speed to the lua profile turn function
* expose whether connection road at turn is incoming or outgoing
* add lua tests for exposed information to turn function
* update docs about attributes in process_turn
* add turn_classification info to docs
* adding warning if uturn and intersection dont match
* handle u turns that do not turn into intersection[0]
* split OSM link generation in an accessible coordinate function

profiles/car.lua

@@ -298,6 +298,14 @@ function setup()
 
     relation_types = Sequence {
       "route"
+    },
+
+    -- classify highway tags when necessary for turn weights
+    highway_turn_classification = {
+    },
+
+    -- classify access tags when necessary for turn weights
+    access_turn_classification = {
     }
   }
 end
@@ -413,7 +421,10 @@ function process_way(profile, way, result, relations)
     WayHandlers.names,
 
     -- set weight properties of the way
-    WayHandlers.weights
+    WayHandlers.weights,
+
+    -- set classification of ways relevant for turns
+    WayHandlers.way_classification_for_turn
   }
 
   WayHandlers.run(profile, way, result, data, handlers, relations)

profiles/lib/way_handlers.lua

@@ -221,6 +221,23 @@ function WayHandlers.hov(profile,way,result,data)
   end
 end
 
+
+-- set highway and access classification by user preference
+function WayHandlers.way_classification_for_turn(profile,way,result,data)
+  local highway = way:get_value_by_key("highway")
+  local access = way:get_value_by_key("access")
+
+  if highway and profile.highway_turn_classification[highway] then
+    assert(profile.highway_turn_classification[highway] < 16, "highway_turn_classification must be smaller than 16")
+    result.highway_turn_classification = profile.highway_turn_classification[highway]
+  end
+  if access and profile.access_turn_classification[access] then
+    assert(profile.access_turn_classification[access] < 16, "access_turn_classification must be smaller than 16")
+    result.access_turn_classification = profile.access_turn_classification[access]
+  end
+end
+
+
 -- check accessibility by traversing our access tag hierarchy
 function WayHandlers.access(profile,way,result,data)
   data.forward_access, data.backward_access =