From d65b099c0df13616f2dd249a45bb14376fa7dcb9 Mon Sep 17 00:00:00 2001
From: jgk <justin.g.kruger@gmail.com>
Date: Sat, 3 Apr 2021 12:14:53 +0200
Subject: [PATCH] Modularise graph functions

---
 src/Dodge/Graph.hs  | 21 +++++++++++++++++++++
 src/Dodge/Layout.hs |  2 +-
 src/Dodge/Path.hs   | 10 +---------
 test/Spec.hs        |  2 ++
 4 files changed, 25 insertions(+), 10 deletions(-)
 create mode 100644 src/Dodge/Graph.hs

diff --git a/src/Dodge/Graph.hs b/src/Dodge/Graph.hs
new file mode 100644
index 000000000..02ad7192e
--- /dev/null
+++ b/src/Dodge/Graph.hs
@@ -0,0 +1,21 @@
+module Dodge.Graph
+  where
+import Data.Function (on)
+import Data.List
+
+import Data.Graph
+
+pairsToIncidence :: (Eq a,Ord a) => [(a,a)] -> [(a,[a])]
+pairsToIncidence = map ((\(xs,ys) -> (head xs,ys)) . unzip)
+                     . groupBy ( (==) `on` fst)
+                     . sort
+
+incidenceToFunction :: Eq a => [(a,[a])] -> a -> [a]
+incidenceToFunction xs a = case lookup a xs of Just ys -> ys
+                                               Nothing -> []
+
+mkNode :: (a,[a]) -> (a,a,[a])
+mkNode (x,xs) = (x,x,xs)
+
+pairsToSCC :: (Eq a, Ord a) => [(a,a)] -> [SCC a]
+pairsToSCC = stronglyConnComp . map mkNode . pairsToIncidence
diff --git a/src/Dodge/Layout.hs b/src/Dodge/Layout.hs
index e421ed7c5..202859817 100644
--- a/src/Dodge/Layout.hs
+++ b/src/Dodge/Layout.hs
@@ -8,7 +8,7 @@ import Dodge.Data
 import Dodge.LevelGen
 import Dodge.Base
 import Dodge.RandomHelp
-import Dodge.Path
+import Dodge.Graph
 import Dodge.Layout.Tree
 import Dodge.Room.Data
 import Dodge.Default
diff --git a/src/Dodge/Path.hs b/src/Dodge/Path.hs
index ae168e341..586cdb73f 100644
--- a/src/Dodge/Path.hs
+++ b/src/Dodge/Path.hs
@@ -1,6 +1,7 @@
 module Dodge.Path where
 import Dodge.Data
 import Dodge.Base
+import Dodge.Graph
 
 import Geometry
 
@@ -160,12 +161,3 @@ maybeToEither :: a -> Maybe b -> Either a b
 maybeToEither _ (Just x) = Right x
 maybeToEither y Nothing  = Left y
 
-pairsToIncidence :: (Eq a,Ord a) => [(a,a)] -> [(a,[a])]
-pairsToIncidence = map ((\(xs,ys) -> (head xs,ys)) . unzip)
-                     . groupBy ( (==) `on` fst)
-                     . sort
-
-incidenceToFunction :: Eq a => [(a,[a])] -> a -> [a]
-incidenceToFunction xs a = case lookup a xs of Just ys -> ys
-                                               Nothing -> []
-
diff --git a/test/Spec.hs b/test/Spec.hs
index cd4753fc9..cf937348d 100644
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -1,2 +1,4 @@
+import Test.QuickCheck
+
 main :: IO ()
 main = putStrLn "Test suite not yet implemented"