X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=VHDL.hs;h=4f4e75cf122ac758be03066ec40c36f261ffbae1;hb=3a611c1075c67670ed6c86a5e74b59b0b379721c;hp=f145385e6c19f932a089d6bae4b62eb8ef0b7952;hpb=0d5cf9c7743e3db5aec159993ce2280493890a19;p=matthijs%2Fmaster-project%2Fc%CE%BBash.git

diff --git a/VHDL.hs b/VHDL.hs
index f145385..4f4e75c 100644
--- a/VHDL.hs
+++ b/VHDL.hs
@@ -27,6 +27,7 @@ import qualified Type
 import qualified Name
 import qualified OccName
 import qualified Var
+import qualified Id
 import qualified TyCon
 import qualified DataCon
 import qualified CoreSubst
@@ -280,8 +281,25 @@ mkConcSm (bndr, app@(CoreSyn.App _ _))= do
 -- least compile for now.
 mkConcSm (bndr, CoreSyn.Var _) = return $ AST.CSPSm $ AST.ProcSm (mkVHDLBasicId "unused") [] []
 
--- A single alt case must be a selector
-mkConcSm (bndr, (Case (Var scrut) b ty [alt])) = error "Single case alt not supported yet"
+-- A single alt case must be a selector. This means thee scrutinee is a simple
+-- variable, the alternative is a dataalt with a single non-wild binder that
+-- is also returned.
+mkConcSm (bndr, expr@(Case (Var scrut) b ty [alt])) =
+  case alt of
+    (DataAlt dc, bndrs, (Var sel_bndr)) -> do
+      case List.elemIndex sel_bndr bndrs of
+        Just i -> do
+          labels <- getFieldLabels (Id.idType scrut)
+          let label = labels!!i
+          let scrut_name = AST.NSimple $ bndrToVHDLId scrut
+          let sel_suffix = AST.SSimple $ label
+          let sel_name = AST.NSelected $ scrut_name AST.:.: sel_suffix 
+          let sel_expr = AST.PrimName sel_name
+          return $ mkUncondAssign bndr sel_expr
+        Nothing -> error $ "VHDL.mkConcSM Not in normal form: Not a selector case:\n" ++ (pprString expr)
+      
+    _ -> error $ "VHDL.mkConcSM Not in normal form: Not a selector case:\n" ++ (pprString expr)
+
 
 -- Multiple case alt are be conditional assignments and have only wild
 -- binders in the alts and only variables in the case values and a variable
@@ -292,16 +310,64 @@ mkConcSm (bndr, (Case (Var scrut) b ty [(_, _, Var false), (con, _, Var true)]))
     cond_expr = (varToVHDLExpr scrut) AST.:=: (conToVHDLExpr con)
     true_expr  = (varToVHDLExpr true)
     false_expr  = (varToVHDLExpr false)
-    false_wform = AST.Wform [AST.WformElem false_expr Nothing]
-    true_wform = AST.Wform [AST.WformElem true_expr Nothing]
-    whenelse = AST.WhenElse true_wform cond_expr
-    dst_name  = AST.NSimple (bndrToVHDLId bndr)
-    assign    = dst_name AST.:<==: (AST.ConWforms [whenelse] false_wform Nothing)
   in
-    return $ AST.CSSASm assign
+    return $ mkCondAssign bndr cond_expr true_expr false_expr
 mkConcSm (_, (Case (Var _) _ _ alts)) = error "VHDL.mkConcSm Not in normal form: Case statement with more than two alternatives"
 mkConcSm (_, Case _ _ _ _) = error "VHDL.mkConcSm Not in normal form: Case statement has does not have a simple variable as scrutinee"
 
+-- Create an unconditional assignment statement
+mkUncondAssign ::
+  CoreBndr -- ^ The signal to assign to
+  -> AST.Expr -- ^ The expression to assign
+  -> AST.ConcSm -- ^ The resulting concurrent statement
+mkUncondAssign bndr expr = mkAssign bndr Nothing expr
+
+-- Create a conditional assignment statement
+mkCondAssign ::
+  CoreBndr -- ^ The signal to assign to
+  -> AST.Expr -- ^ The condition
+  -> AST.Expr -- ^ The value when true
+  -> AST.Expr -- ^ The value when false
+  -> AST.ConcSm -- ^ The resulting concurrent statement
+mkCondAssign bndr cond true false = mkAssign bndr (Just (cond, true)) false
+
+-- Create a conditional or unconditional assignment statement
+mkAssign ::
+  CoreBndr -> -- ^ The signal to assign to
+  Maybe (AST.Expr , AST.Expr) -> -- ^ Optionally, the condition to test for
+                                 -- and the value to assign when true.
+  AST.Expr -> -- ^ The value to assign when false or no condition
+  AST.ConcSm -- ^ The resulting concurrent statement
+
+mkAssign bndr cond false_expr =
+  let
+    -- I'm not 100% how this assignment AST works, but this gets us what we
+    -- want...
+    whenelse = case cond of
+      Just (cond_expr, true_expr) -> 
+        let 
+          true_wform = AST.Wform [AST.WformElem true_expr Nothing] 
+        in
+          [AST.WhenElse true_wform cond_expr]
+      Nothing -> []
+    false_wform = AST.Wform [AST.WformElem false_expr Nothing]
+    dst_name  = AST.NSimple (bndrToVHDLId bndr)
+    assign    = dst_name AST.:<==: (AST.ConWforms whenelse false_wform Nothing)
+  in
+    AST.CSSASm assign
+  
+-- Finds the field labels for VHDL type generated for the given Core type,
+-- which must result in a record type.
+getFieldLabels :: Type.Type -> VHDLState [AST.VHDLId]
+getFieldLabels ty = do
+  -- Ensure that the type is generated (but throw away it's VHDLId)
+  vhdl_ty ty
+  -- Get the types map, lookup and unpack the VHDL TypeDef
+  types <- getA vsTypes
+  case Map.lookup (OrdType ty) types of
+    Just (_, AST.TDR (AST.RecordTypeDef elems)) -> return $ map (\(AST.ElementDec id _) -> id) elems
+    _ -> error $ "VHDL.getFieldLabels Type not found or not a record type? This should not happen! Type: " ++ (show ty)
+
 -- Turn a variable reference into a AST expression
 varToVHDLExpr :: Var.Var -> AST.Expr
 varToVHDLExpr var = AST.PrimName $ AST.NSimple $ bndrToVHDLId var