ALGO: use isInsidePoly

Algebra/Polygon.hs

@@ -24,3 +24,12 @@ polySegments p@(x':_:_:_) = go p ++ [(last p, x')]
     go (x:y:xs) = (x, y) : go (y:xs)
     go _        = []
 polySegments _ = []
+
+
+isInsidePoly :: [PT] -> Segment -> Bool
+isInsidePoly pts seg =
+  null
+    . catMaybes
+    . fmap (intersectSeg'' seg)
+    $ polySegments pts
+

Algorithms/PolygonTriangulation.hs

@@ -131,11 +131,7 @@ monotoneDiagonals pts = catMaybes . go $ classifyList pts
     go [] = []
     getSeg [] _ _ = Nothing
     getSeg (z:zs) pt pts'
-      | null
-        . catMaybes
-        . fmap (intersectSeg'' (z, pt))
-        $ polySegments pts
-        = Just (z, pt)
+      | isInsidePoly pts (z, pt) = Just (z, pt)
       | otherwise = getSeg zs pt pts'
     aboveS pt pts' = tail . dropWhile (/= pt) $ sortedYX pts'
     belowS pt pts' = reverse . takeWhile (/= pt) $ sortedYX pts'