incomplete support for record types in the abstract syntax

src/GF/Compile/TC.hs

@@ -23,9 +23,12 @@ module GF.Compile.TC (AExp(..),
 import GF.Data.Operations
 import GF.Grammar.Predef
 import GF.Grammar.Abstract
+import GF.Grammar.Printer
 
 import Control.Monad
 import Data.List (sortBy)
+import Data.Maybe
+import Text.PrettyPrint
 
 data AExp =
      AVr   Ident Val 
@@ -39,9 +42,15 @@ data AExp =
    | AAbs  Ident Val AExp 
    | AProd Ident AExp AExp 
    | AEqs  [([Exp],AExp)] --- not used
+   | ARecType [ALabelling]
+   | AR    [AAssign]
+   | AP    AExp Label Val
    | AData Val
   deriving (Eq,Show)
 
+type ALabelling = (Label, AExp) 
+type AAssign = (Label, (Val, AExp))
+
 type Theory = QIdent -> Err Val
 
 lookupConst :: Theory -> QIdent -> Err Val
@@ -79,6 +88,8 @@ eval env e = ---- errIn ("eval" +++ prt e +++ "in" +++ prEnv env) $
   QC m c  -> return $ VCn (m,c) ---- == Q ?
   Sort c  -> return $ VType --- the only sort is Type
   App f a -> join $ liftM2 app (eval env f) (eval env a)
+  RecType xs -> do xs <- mapM (\(l,e) -> eval env e >>= \e -> return (l,e)) xs
+                   return (VRecType xs)
   _ -> return $ VClos env e
 
 eqVal :: Int -> Val -> Val -> Err [(Val,Val)]
@@ -132,6 +143,19 @@ checkExp th tenv@(k,rho,gamma) e ty = do
       (b',csb) <- checkType th (k+1, (x,v x):rho, (x,VClos rho a):gamma) b
       return (AProd x a' b', csa ++ csb)
 
+    R xs -> 
+      case typ of
+        VRecType ys -> do case [l | (l,_) <- ys, isNothing (lookup l xs)] of
+                            [] -> return ()
+                            ls -> fail (render (text "no value given for label:" <+> fsep (punctuate comma (map ppLabel ls))))
+                          r <- mapM (checkAssign th tenv ys) xs
+                          let (xs,css) = unzip r
+                          return (AR xs, concat css)
+        _           -> prtBad ("record type expected for" +++ prt e +++ "instead of") typ
+
+    P r l -> do (r',cs) <- checkExp th tenv r (VRecType [(l,typ)])
+                return (AP r' l typ,cs)
+
     _ -> checkInferExp th tenv e typ
 
 checkInferExp :: Theory -> TCEnv -> Exp -> Val -> Err (AExp, [(Val,Val)])
@@ -151,6 +175,9 @@ inferExp th tenv@(k,rho,gamma) e = case e of
    EFloat i -> return (AFloat i, valAbsFloat, [])
    K i -> return (AStr i, valAbsString, [])
    Sort _ -> return (AType, vType, [])
+   RecType xs -> do r <- mapM (checkLabelling th tenv) xs
+                    let (xs,css) = unzip r
+                    return (ARecType xs, vType, concat css)
    App f t -> do
     (f',w,csf) <- inferExp th tenv f 
     typ <- whnf w
@@ -162,6 +189,27 @@ inferExp th tenv@(k,rho,gamma) e = case e of
       _ -> prtBad ("Prod expected for function" +++ prt f +++ "instead of") typ
    _ -> prtBad "cannot infer type of expression" e
 
+checkLabelling :: Theory -> TCEnv -> Labelling -> Err (ALabelling, [(Val,Val)])
+checkLabelling th tenv (lbl,typ) = do
+  (atyp,cs) <- checkType th tenv typ
+  return ((lbl,atyp),cs)
+
+checkAssign :: Theory -> TCEnv -> [(Label,Val)] -> Assign -> Err (AAssign, [(Val,Val)])
+checkAssign th tenv@(k,rho,gamma) typs (lbl,(Just typ,exp)) = do
+  (atyp,cs1) <- checkType th tenv typ
+  val <- eval rho typ
+  cs2 <- case lookup lbl typs of
+           Nothing   -> return []
+           Just val0 -> eqVal k val val0
+  (aexp,cs3) <- checkExp th tenv exp val
+  return ((lbl,(val,aexp)),cs1++cs2++cs3)
+checkAssign th tenv@(k,rho,gamma) typs (lbl,(Nothing,exp)) = do
+  case lookup lbl typs of
+    Nothing  -> do (aexp,val,cs) <- inferExp th tenv exp
+                   return ((lbl,(val,aexp)),cs)
+    Just val -> do (aexp,cs) <- checkExp th tenv exp val
+                   return ((lbl,(val,aexp)),cs)
+
 checkBranch :: Theory -> TCEnv -> Equation -> Val -> Err (([Exp],AExp),[(Val,Val)])
 checkBranch th tenv b@(ps,t) ty = errIn ("branch" +++ show b) $ 
                                   chB tenv' ps' ty 

src/GF/Grammar/MMacros.hs

@@ -186,6 +186,8 @@ val2expP safe v = case v of
   VGen i x  -> if safe 
                then prtBad "unsafe val2exp" v
                else return $ Vr $ x  --- in editing, no alpha conversions presentv
+  VRecType xs->do xs <- mapM (\(l,v) -> val2expP safe v >>= \e -> return (l,e)) xs
+                  return (RecType xs)
   VType     -> return typeType
  where 
    substVal g e = mapPairsM (val2expP safe) g >>= return . (\s -> substTerm [] s e)

src/GF/Grammar/PrGrammar.hs

@@ -189,6 +189,7 @@ instance Print Val where
   prt (VClos env e) = case e of
     Meta _ -> prt_ e ++ prEnv env
     _      -> prt_ e ---- ++ prEnv env ---- for debugging
+  prt (VRecType xs) = prCurly (concat (intersperse "," [prt l ++ "=" ++ prt v | (l,v) <- xs]))
   prt VType = "Type"
  
 prv1 v = case v of

src/GF/Grammar/Unify.hs

@@ -65,6 +65,7 @@ unify e1 e2 g =
   (App c a, App d b)            -> case unify c d g of 
                                      Ok g1 -> unify a b g1 
                                      _       -> prtBad "fail unify" e1
+  (RecType xs,RecType ys) | xs == ys -> return g
   _                             -> prtBad "fail unify" e1
 
 extend :: Unifier -> MetaSymb -> Term -> Err Unifier

src/GF/Grammar/Values.hs

@@ -35,7 +35,7 @@ import GF.Grammar.Predef
 
 type Exp = Term
 
-data Val = VGen Int Ident | VApp Val Val | VCn QIdent | VType | VClos Env Exp 
+data Val = VGen Int Ident | VApp Val Val | VCn QIdent | VRecType [(Label,Val)] | VType | VClos Env Exp 
   deriving (Eq,Show)
 
 type Env = [(Ident,Val)]