Update Path class to allow different distances

jumper/core/path.lua

@@ -67,12 +67,15 @@ if (...) then
 
   --- Evaluates the `path` length
   -- @class function
+  -- @tparam function heuristic Optional heuristic function for determining.
+  -- distance between nodes. Default: @{Heuristic.EUCLIDIAN}.
   -- @treturn number the `path` length
 	-- @usage local len = p:getLength()
-  function Path:getLength()
+  function Path:getLength(heuristic)
+    local heuristic = heuristic or Heuristic.EUCLIDIAN
     local len = 0
     for i = 2,#self._nodes do
-      len = len + Heuristic.EUCLIDIAN(self._nodes[i], self._nodes[i-1])
+      len = len + heuristic(self._nodes[i], self._nodes[i-1])
     end
     return len
   end
@@ -193,6 +196,18 @@ if (...) then
 		return self
 	end
 
+
+  --- Return a simplified form of the path.
+  -- @treturn table Array of `{x, y}` values in the path.
+  -- @usage x1, y1 = unpack(path:simplify()[1])
+  function Path:simplify()
+      local simple = {}
+      for node in self:iter() do
+          simple[#simple + 1] = {node._x, node._y}
+      end
+      return simple
+  end
+
   return setmetatable(Path,
     {__call = function(self,...)
       return Path:new(...)

specs/path_specs.lua

@@ -43,6 +43,12 @@ context('Module Path', function()
 			p = Path()
 			for i = 1,10 do p._nodes[#p._nodes+1] = Node(i,i) end
 			assert_less_than(p:getLength()-9*math.sqrt(2),1e-6)			
+
+			--Test with diagonal distance
+			local Heuristics = require ('jumper.core.heuristics')
+			p = Path()
+			for i = 1,10 do p._nodes[#p._nodes+1] = Node(i,i) end
+			assert_equal(p:getLength(Heuristics.DIAGONAL), 9)
 		end)
 
 		test('Path:fill() interpolates a path', function()

specs/pathfinder_specs.lua

@@ -140,7 +140,7 @@ context('Module Pathfinder', function()
 			assert_equal(pf:getFinder(), 'ASTAR')
 		end)
 
-		test('Passing nil sets \'ASTAR\` as the finder if no previous finder was set, is \'ASTAR\'', function()
+		test('Passing nil sets \'ASTAR\' as the finder if no previous finder was set, is \'ASTAR\'', function()
 			local pf = PF(grid)
 			pf:setFinder()
 			assert_equal(pf:getFinder(), 'ASTAR')