add div by zero protection + some indentions fixes

2 files changed, 96 insertions, 42 deletions

diff --git a/AufgabeFFP6.hs b/AufgabeFFP6.hs
index c60053d..1f2faff 100644
--- a/AufgabeFFP6.hs
+++ b/AufgabeFFP6.hs
@@ -4,6 +4,7 @@ module AufgabeFFP6
 where
 
 import Data.Array
+import Debug.Trace
 
 type F  = Array Int Int
 type Op = Int -> Int -> Int
@@ -33,11 +34,30 @@ yield = yield_bt
 
 --------------------------------------------------------------------------------
 
+instance Eq (Integer -> Integer -> Integer) where
+  (==) op1 op2 = ((op1 3 3) - (op2 3 3)) == 0
+instance Eq (Int -> Int -> Int) where
+  (==) op1 op2 = ((op1 3 3) - (op2 3 3)) == 0
+
+check_divByZero :: F -> G -> Bool
+check_divByZero f g = check_divByZero' (tail (elems f)) (elems g)
+  where
+    check_divByZero' _ [] = True
+    check_divByZero' [] _ = True
+    check_divByZero' (f:fs) (g:gs)
+      | f == 0 && g == (./.) = False
+      | otherwise = True && check_divByZero' fs gs
+
+--------------------------------------------------------------------------------
+
 type Node = ([Int], [Int], W, [Op])
 
 goal_yield_bt :: Node -> Bool
 goal_yield_bt (_, _, _, []) = False -- no operators
-goal_yield_bt (f, [], w, g) = eval (listArray (1, length f) f) (listArray (1, length g) g) == w
+goal_yield_bt (f, [], w, g) = check_divByZero f' g' && eval f' g' == w
+  where
+    f' = listArray (1, length f) f
+    g' = listArray (1, length g) g
 goal_yield_bt (_, _, _, _) = False
 
 succ_yield_bt :: Node -> [Node]
@@ -93,31 +113,31 @@ yield_gtf = filt . transform . generate
 
 -- produce [G] by using get_combinations
 generate :: F -> W -> (F, W, [G])
-generate f w =  (f, w, [ array (1,n) entries | entries <- get_combinations n ] )
-        where 
-        n = (snd $ bounds f) - 1
+generate f w =  (f, w, [ array (1,n) entries | entries <- get_combinations n ])
+  where
+    n = (snd $ bounds f) - 1
 
--- provide all selections of length n, work recursively and attach index for level (convenient for creating arrays)
+-- provide all selections of length n, work recursively and attach index for
+-- level (convenient for creating arrays)
 get_combinations :: Int -> [[(Int, Op)]]
-get_combinations 1 = [[(1,(+))], [(1, (-))], [(1, (*))], [(1,(./.))]]
+get_combinations 1 = [[(1,(+))], [(1,(-))], [(1,(*))], [(1,(./.))]]
 get_combinations n = [ (up i) ++ entr  | entr <- get_combinations (n-1), i <- get_combinations 1 ]
-        where 
-        up = map (\(num, x) -> ((num+n-1), x))
+  where
+    up = map (\(num, x) -> ((num + n - 1), x))
 
--- attaches a list of results 
-transform ::  (W -> (F,W,[G])) -> W -> ((F, W, [G]), [W])
-transform fun w = ((f, w, g), map (eval f) g )
-        where 
-        (f, w, g) = fun w
+-- attaches a list of results
+transform ::  (W -> (F, W, [G])) -> W -> ((F, W, [G]), [W])
+transform fun w = ((f, w, g'), map (eval f) g')
+  where
+    (f, w, g) = fun w
+    g' = filter (\g'' -> check_divByZero f g'') g
 
--- take those, where the entry in the result list corresponds to 
-filt :: (W -> ((F,W,[G]),[W]) ) -> W -> [G]
+-- take those, where the entry in the result list corresponds to
+filt :: (W -> ((F, W, [G]), [W]) ) -> W -> [G]
 filt fun w = [ g!!i | i <- [0..n], res!!i == w ]
-        where
-        ( (f, _, g), res ) = fun w
-        n = (length g) - 1
-
-
+  where
+    ( (f, _, g), res ) = fun w
+    n = (length g) - 1
 
 --------------------------------------------------------------------------------
 
diff --git a/TestAufgabeFFP6.hs b/TestAufgabeFFP6.hs
index c435045..1f661e6 100644
--- a/TestAufgabeFFP6.hs
+++ b/TestAufgabeFFP6.hs
@@ -13,39 +13,73 @@ cases1 = TestLabel "eval" $ TestList [
   TestCase $ assertEqual "eval3" (-3)
     (eval (array (1,3) [(1,1), (2,2), (3,3)]) (array (1,2) [(1,(-)), (2,(*))])),
   TestCase $ assertEqual "eval4" (-1)
-    (eval (array (1,6) [(1,3), (2,5), (3,2), (4,-2), (5,7), (6,0)]) (array (1,5) [(1,(+)), (2,(./.)), (3,(*)), (4,(+)), (5,(-))])),
+    (eval (array (1,6) [(1,3), (2,5), (3,2), (4,-2), (5,7), (6,0)])
+      (array (1,5) [(1,(+)), (2,(./.)), (3,(*)), (4,(+)), (5,(-))])),
   TestCase $ assertEqual "eval5" (1)
-    (eval (array (1,6) [(1,3), (2,5), (3,2), (4,-2), (5,7), (6,0)]) (array (1,5) [(1,(*)), (2,(-)), (3,(+)), (4,(./.)), (5,(+))])),
+    (eval (array (1,6) [(1,3), (2,5), (3,2), (4,-2), (5,7), (6,0)])
+      (array (1,5) [(1,(*)), (2,(-)), (3,(+)), (4,(./.)), (5,(+))])),
   TestCase $ assertEqual "eval6" (-5)
-    (eval (array (1,6) [(1,4), (2,2), (3,3), (4,-4), (5,5), (6,2)]) (array (1,5) [(1,(+)), (2,(./.)), (3,(*)), (4,(+)), (5,(-))])),
+    (eval (array (1,6) [(1,4), (2,2), (3,3), (4,-4), (5,5), (6,2)])
+      (array (1,5) [(1,(+)), (2,(./.)), (3,(*)), (4,(+)), (5,(-))])),
   TestCase $ assertEqual "eval7" (2)
-    (eval (array (1,6) [(1,4), (2,2), (3,3), (4,-4), (5,5), (6,2)]) (array (1,5) [(1,(*)), (2,(-)), (3,(+)), (4,(./.)), (5,(+))]))
+    (eval (array (1,6) [(1,4), (2,2), (3,3), (4,-4), (5,5), (6,2)])
+      (array (1,5) [(1,(*)), (2,(-)), (3,(+)), (4,(./.)), (5,(+))]))
   ]
 
-instance Eq (Integer -> Integer -> Integer) where
-        (==) op1 op2 = ((op1 3 3) - (op2 3 3)) == 0
-instance Eq (Int -> Int -> Int) where
-        (==) op1 op2 = ((op1 3 3) - (op2 3 3)) == 0
+--------------------------------------------------------------------------------
 
 cases2 =  TestLabel "yield_bt"  $ TestList [
-                TestCase $ assertEqual "yield_bt1" (yield_bt (array (1,3) [(1,1),(2,2),(3,3)] ) 6)
-                                 [array (1,2) [(1,(+)),(2,(+))],array (1,2) [(1,(*)),(2,(*))]],
-                TestCase $ assertEqual "yield_bt2" (yield_bt (array (1,3) [(1,1),(2,2),(3,3)] ) 4) [],
-                TestCase $ assertEqual "yield_bt3" (yield_bt (array (1,3) [(1,1),(2,2),(3,3)]) 0)
-                                [(array (1,2) [(1,(+)),(2,(-))]),(array (1,2) [(1,(*)),(2,(./.))]),(array (1,2) [(1,(./.)),(2,(*))]),(array (1,2) [(1,(./.)),(2,(./.))])]
-                                 ]
-
+  TestCase $ assertEqual "yield_bt1"
+    [array (1,2) [(1,(+)), (2,(+))],array (1,2) [(1,(*)), (2,(*))]]
+    (yield_bt (array (1,3) [(1,1), (2,2), (3,3)] ) 6),
+  TestCase $ assertEqual "yield_bt2"
+    []
+    (yield_bt (array (1,3) [(1,1), (2,2), (3,3)] ) 4),
+  TestCase $ assertEqual "yield_bt3"
+    [(array (1,2) [(1,(+)), (2,(-))]),(array (1,2) [(1,(*)), (2,(./.))]),
+      (array (1,2) [(1,(./.)), (2,(*))]),(array (1,2) [(1,(./.)), (2,(./.))])]
+    (yield_bt (array (1,3) [(1,1), (2,2), (3,3)]) 0),
+  TestCase $ assertEqual "yield_bt4"
+    [array (1,1) [(1,(+))], array (1,1) [(1,(-))]]
+    (yield_bt (array (1,2) [(1,1), (2,0)]) 1)
+   ]
 
 cases3 =  TestLabel "yield_gtf"  $ TestList [
-                TestCase $ assertEqual "yield_gtf1" (yield_gtf (array (1,3) [(1,1),(2,2),(3,3)] ) 6)
-                                 [array (1,2) [(1,(+)),(2,(+))],array (1,2) [(1,(*)),(2,(*))]],
-                TestCase $ assertEqual "yield_gtf2" (yield_gtf (array (1,3) [(1,1),(2,2),(3,3)] ) 4) [],
-                TestCase $ assertEqual "yield_gtf3" (yield_gtf (array (1,3) [(1,1),(2,2),(3,3)]) 0)
-                                [(array (1,2) [(1,(+)),(2,(-))]),(array (1,2) [(1,(*)),(2,(./.))]),(array (1,2) [(1,(./.)),(2,(*))]),(array (1,2) [(1,(./.)),(2,(./.))])]
-                                 ]
+  TestCase $ assertEqual "yield_gtf1"
+    [array (1,2) [(1,(+)), (2,(+))],array (1,2) [(1,(*)), (2,(*))]]
+    (yield_gtf (array (1,3) [(1,1), (2,2), (3,3)] ) 6),
+  TestCase $ assertEqual "yield_gtf2"
+    []
+    (yield_gtf (array (1,3) [(1,1), (2,2), (3,3)] ) 4),
+  TestCase $ assertEqual "yield_gtf3"
+    [(array (1,2) [(1,(+)), (2,(-))]),(array (1,2) [(1,(*)), (2,(./.))]),
+      (array (1,2) [(1,(./.)), (2,(*))]),(array (1,2) [(1,(./.)), (2,(./.))])]
+    (yield_gtf (array (1,3) [(1,1), (2,2), (3,3)]) 0),
+  TestCase $ assertEqual "yield_gtf4"
+    [array (1,1) [(1,(+))], array (1,1) [(1,(-))]]
+    (yield_gtf (array (1,2) [(1,1), (2,0)]) 1)
+   ]
+
+cases4 =  TestLabel "yield"  $ TestList [
+  TestCase $ assertEqual "yield"
+    [array (1,2) [(1,(+)), (2,(+))],array (1,2) [(1,(*)), (2,(*))]]
+    (yield (array (1,3) [(1,1), (2,2), (3,3)] ) 6),
+  TestCase $ assertEqual "yield"
+    []
+    (yield (array (1,3) [(1,1), (2,2), (3,3)] ) 4),
+  TestCase $ assertEqual "yield"
+    [(array (1,2) [(1,(+)), (2,(-))]),(array (1,2) [(1,(*)), (2,(./.))]),
+      (array (1,2) [(1,(./.)), (2,(*))]),(array (1,2) [(1,(./.)), (2,(./.))])]
+    (yield (array (1,3) [(1,1), (2,2), (3,3)]) 0),
+  TestCase $ assertEqual "yield"
+    [array (1,1) [(1,(+))], array (1,1) [(1,(-))]]
+    (yield (array (1,2) [(1,1), (2,0)]) 1)
+   ]
+
+--------------------------------------------------------------------------------
 
 tests :: [Test]
-tests = [cases1, cases2, cases3]
+tests = [cases1, cases2, cases3, cases4]
 
 main = do
   forM tests $ \test ->