Add edge type data type

dfs.tidal

@@ -8,6 +8,9 @@ import Data.List
 
 import qualified Data.Array as A
 
+-- Tree, Forward, Back, Cross, Loop, No Edge
+data EdgeType = T | F | B | X | L | NE deriving Show
+--
 tabulate :: Bounds -> [Vertex] -> Table Int
 tabulate bnds vs = A.array bnds (zip vs [1..])
 --
@@ -51,15 +54,24 @@ pairfastcat = (\(u,v) -> fastcat $ pure <$> [u,v])
 nodeEdgePairs :: Graph -> [(Vertex,[Edge])]
 nodeEdgePairs g = map (\u -> (u,[(u,v)| v <- g ! u])) $ preorderF $ dff g
 --
-instrument :: Graph -> Edge -> [Char]
-instrument g e
-  | p treeG = "clubkick"
-  | p forwardG = "superpwm"
-  | p backG = "casio"
-  | p crossG = "amencutup"
-  | otherwise = "sn" -- edge is (x,x)
+edgeType :: Graph -> Edge -> EdgeType
+edgeType g e@(x,y)
+  | p treeG = T
+  | p forwardG = F
+  | p backG = B
+  | p crossG = X
+  | x == y = L
+  | otherwise = NE
     where p f = e `elem` (f g)
 --
+instrument :: Graph -> Edge -> [Char]
+instrument g e = case edgeType g e of
+        T -> "clubkick"
+        F -> "superpwm"
+        B -> "casio"
+        X -> "amencutup"
+        L -> "sn"
+        NE -> " " -- let super collider deal with it
 -- complete graph
 k n = buildG (1,n) [(u,v)|u <- [1..n],v <- [1..n]]
 -- path