show error messages on bad input/state

1 files changed, 20 insertions, 17 deletions

diff --git a/src/Mind.hs b/src/Mind.hs
index 359293c..d686e24 100644
--- a/src/Mind.hs
+++ b/src/Mind.hs
@@ -76,12 +76,15 @@ insertEdge ns i e
 
 
 -- network computation
-compute :: Network -> [Float] -> [Float] -> Maybe ([Float], [Float])
-compute net input state = 
-  let 
-    s = newState net input state
-    state' = map (Just) s
-  in Just $ (output net input state state', s)
+compute :: Network -> [Float] -> [Float] -> Either String ([Float], [Float])
+compute net input state 
+ | (length input) /= (numInput net) = Left $ "Bad input length: " ++ (show $ length input)
+ | (length state) /= (length $ internalNeurons net) = Left $ "Bad state length: " ++ (show $ length state)  
+ | otherwise = 
+   let 
+      s = newState net input state
+      state' = map (Just) s
+    in Right $ (output net input state state', s)
 
 
 type InputState = ([Float], [Float])
@@ -89,7 +92,7 @@ type NewState = [Maybe Float]
 
 
 output :: Network -> [Float] -> [Float] -> NewState -> [Float]
-output net input state state'= 
+output net input state state' = 
   let 
     numOutput = length $ outputNeurons net
   in 
@@ -97,16 +100,16 @@ output net input state state'=
 
 newState :: Network -> [Float] -> [Float] -> [Float]
 newState net input state =
-  let numInternal = length $ internalNeurons net
-  in fst $ 
-    foldr 
-    (\x (r, ns) ->
-      let (value, ns') = getValue net (input, state) ns (Internal x)
-      in (value:r, ns')
-    )
-    ([], replicate numInternal Nothing)
-    [0..numInternal-1]
-
+    let numInternal = length $ internalNeurons net
+    in fst $ 
+      foldr 
+      (\x (r, ns) ->
+        let (value, ns') = getValue net (input, state) ns (Internal x)
+        in (value:r, ns')
+      )
+      ([], replicate numInternal Nothing)
+      [0..numInternal-1]
+  
 
 
 updateValue :: NewState -> Int -> Float -> NewState