Add ELIF statements and refactor IF blocks

1 files changed, 6 insertions, 18 deletions

diff --git a/DSL/Interpretation.hs b/DSL/Interpretation.hs
index 02f741d..e68b64f 100644
--- a/DSL/Interpretation.hs
+++ b/DSL/Interpretation.hs
@@ -61,26 +61,15 @@ applyOperation m (OpCall name)           = applyCall name m
 applyLinear :: Machine -> [Operation] -> IO Machine
 applyLinear = foldlM applyOperation
 
-applyIf :: [Block] -> [Block] -> Machine -> IO Machine
-applyIf _ _ m@Machine{ ok=False } = return m
-applyIf c b m                     = do
+applyIf :: [Block] -> [Block] -> [Block] -> Machine -> IO Machine
+applyIf _ _ _ m@Machine{ ok=False } = return m
+applyIf c t f m                     = do
   m' <- evalBlocks c m
   case m' of
     Machine{ ok=False }                 -> return m'
     Machine{ stack=[] }                 -> hcf m' "IF: stack underflow"
-    Machine{ stack=StackBool False:xs } -> return m'{ stack=xs }
-    Machine{ stack=StackBool True:xs }  -> evalBlocks b m'{ stack=xs }
-    Machine{ stack=_:_ }                -> hcf m' "IF: type mis-match"
-
-applyIfElse :: [Block] -> [Block] -> [Block] -> Machine -> IO Machine
-applyIfElse _ _ _ m@Machine{ ok=False } = return m
-applyIfElse c b1 b2 m                   = do
-  m' <- evalBlocks c m
-  case m' of
-    Machine{ ok=False }                 -> return m'
-    Machine{ stack=[] }                 -> hcf m' "IFELSE: stack underflow"
-    Machine{ stack=StackBool True:xs }  -> evalBlocks b1 m'{ stack=xs }
-    Machine{ stack=StackBool False:xs } -> evalBlocks b2 m'{ stack=xs }
+    Machine{ stack=StackBool True:xs }  -> evalBlocks t m'{ stack=xs }
+    Machine{ stack=StackBool False:xs } -> evalBlocks f m'{ stack=xs }
     Machine{ stack=_:_ }                -> hcf m' "IF: type mis-match"
 
 applyWhile :: [Block] -> [Block] -> Machine -> IO Machine
@@ -100,8 +89,7 @@ evalBlocks :: [Block] -> Machine -> IO Machine
 evalBlocks _ m@Machine{ ok=False } = return m
 evalBlocks [] m                    = return m
 evalBlocks (BLinear b:bs) m        = applyLinear m b >>= evalBlocks bs
-evalBlocks (BIf c b:bs) m          = applyIf c b m >>= evalBlocks bs
-evalBlocks (BIfElse c b1 b2:bs) m  = applyIfElse c b1 b2 m >>= evalBlocks bs
+evalBlocks (BIf c t f:bs) m        = applyIf c t f m >>= evalBlocks bs
 evalBlocks (BWhile c b:bs) m       = applyWhile c b m >>= evalBlocks bs
 
 interpret :: ([ProcSpec], Program) -> IO ()