syntax for inaccessible patterns in GF

4 files changed, 25 insertions, 11 deletions

diff --git a/src/runtime/haskell/PGF.hs b/src/runtime/haskell/PGF.hs
index a2a2154bb..9cb23bf50 100644
--- a/src/runtime/haskell/PGF.hs
+++ b/src/runtime/haskell/PGF.hs
@@ -302,7 +302,8 @@ browse pgf id = fmap (\def -> (def,producers,consumers)) definition
                    Just (ty,_,Just eqs) -> Just $ render (text "fun" <+> ppCId id <+> colon <+> ppType 0 [] ty $$
                                                           if null eqs
                                                             then empty
-                                                            else text "def" <+> vcat [let (scope,ds) = mapAccumL (ppPatt 9) [] patts
+                                                            else text "def" <+> vcat [let scope = foldl pattScope [] patts
+                                                                                          ds    = map (ppPatt 9 scope) patts
                                                                                       in ppCId id <+> hsep ds <+> char '=' <+> ppExpr 0 scope res | Equ patts res <- eqs])
                    Just (ty,_,Nothing ) -> Just $ render (text "data" <+> ppCId id <+> colon <+> ppType 0 [] ty)
                    Nothing   -> case Map.lookup id (cats (abstract pgf)) of
diff --git a/src/runtime/haskell/PGF/Binary.hs b/src/runtime/haskell/PGF/Binary.hs
index bc46390f4..424eabe71 100644
--- a/src/runtime/haskell/PGF/Binary.hs
+++ b/src/runtime/haskell/PGF/Binary.hs
@@ -128,6 +128,7 @@ instance Binary Patt where
   put PWild        = putWord8 2

   put (PLit l)     = putWord8 3 >> put l

   put (PImplArg p) = putWord8 4 >> put p

+  put (PTilde p)   = putWord8 5 >> put p

   get = do tag <- getWord8

            case tag of

              0 -> liftM2 PApp get get

@@ -135,6 +136,7 @@ instance Binary Patt where
              2 -> return PWild

              3 -> liftM  PLit get

              4 -> liftM  PImplArg get

+             5 -> liftM  PTilde get

              _ -> decodingError

 

 instance Binary Equation where

diff --git a/src/runtime/haskell/PGF/Expr.hs b/src/runtime/haskell/PGF/Expr.hs
index 7d88eb798..e23f4d672 100644
--- a/src/runtime/haskell/PGF/Expr.hs
+++ b/src/runtime/haskell/PGF/Expr.hs
@@ -1,5 +1,5 @@
 module PGF.Expr(Tree, BindType(..), Expr(..), Literal(..), Patt(..), Equation(..),

-                readExpr, showExpr, pExpr, pBinds, ppExpr, ppPatt,

+                readExpr, showExpr, pExpr, pBinds, ppExpr, ppPatt, pattScope,

 

                 mkApp,    unApp,

                 mkStr,    unStr,

@@ -68,6 +68,7 @@ data Patt =
  | PVar CId                         -- ^ variable

  | PWild                            -- ^ wildcard

  | PImplArg Patt                    -- ^ implicit argument in pattern

+ | PTilde Expr

   deriving Show

 

 -- | The equation is used to define lambda function as a sequence

@@ -223,14 +224,22 @@ ppExpr d scope (EVar i)     = ppCId (scope !! i)
 ppExpr d scope (ETyped e ty)= PP.char '<' PP.<> ppExpr 0 scope e PP.<+> PP.colon PP.<+> ppType 0 scope ty PP.<> PP.char '>'

 ppExpr d scope (EImplArg e) = PP.braces (ppExpr 0 scope e)

 

-ppPatt :: Int -> [CId] -> Patt -> ([CId],PP.Doc)

-ppPatt d scope (PApp f ps) = let (scope',ds) = mapAccumL (ppPatt 2) scope ps

-                             in (scope',ppParens (not (List.null ps) && d > 1) (ppCId f PP.<+> PP.hsep ds))

-ppPatt d scope (PLit l)    = (scope,ppLit l)

-ppPatt d scope (PVar f)    = (f:scope,ppCId f)

-ppPatt d scope PWild       = (scope,PP.char '_')

-ppPatt d scope (PImplArg p) = let (scope',d) = ppPatt 0 scope p

-                              in (scope',PP.braces d)

+ppPatt :: Int -> [CId] -> Patt -> PP.Doc

+ppPatt d scope (PApp f ps)  = let ds = List.map (ppPatt 2 scope) ps

+                              in ppParens (not (List.null ps) && d > 1) (ppCId f PP.<+> PP.hsep ds)

+ppPatt d scope (PLit l)     = ppLit l

+ppPatt d scope (PVar f)     = ppCId f

+ppPatt d scope PWild        = PP.char '_'

+ppPatt d scope (PImplArg p) = PP.braces (ppPatt 0 scope p)

+ppPatt d scope (PTilde e)   = PP.char '~' PP.<> ppExpr 6 scope e

+

+pattScope :: [CId] -> Patt -> [CId]

+pattScope scope (PApp f ps)  = foldl pattScope scope ps

+pattScope scope (PLit l)     = scope

+pattScope scope (PVar f)     = f:scope

+pattScope scope PWild        = scope

+pattScope scope (PImplArg p) = pattScope scope p                               

+pattScope scope (PTilde e)   = scope

 

 ppBind Explicit x = ppCId x

 ppBind Implicit x = PP.braces (ppCId x)

@@ -362,5 +371,6 @@ match sig f eqs as0 =
         tryMatch (PApp f1 ps1) (VApp f2 vs2      ) env | f1 == f2 = tryMatches eqs (ps1++ps) (vs2++as) res env

         tryMatch (PLit l1    ) (VLit l2          ) env | l1 == l2 = tryMatches eqs  ps        as  res env

         tryMatch (PImplArg p ) (VImplArg v       ) env            = tryMatch p v env

+        tryMatch (PTilde _   ) (_                ) env            = tryMatches eqs  ps        as  res env

         tryMatch _             _                   env            = match sig f eqs as0

 

diff --git a/src/runtime/haskell/PGF/Printer.hs b/src/runtime/haskell/PGF/Printer.hs
index 353b06f86..23bdc718d 100644
--- a/src/runtime/haskell/PGF/Printer.hs
+++ b/src/runtime/haskell/PGF/Printer.hs
@@ -35,7 +35,8 @@ ppFun :: CId -> (Type,Int,Maybe [Equation]) -> Doc
 ppFun f (t,_,Just eqs) = text "fun" <+> ppCId f <+> colon <+> ppType 0 [] t $$
                          if null eqs
                            then empty
-                           else text "def" <+> vcat [let (scope,ds) = mapAccumL (ppPatt 9) [] patts
+                           else text "def" <+> vcat [let scope = foldl pattScope [] patts
+                                                         ds    = map (ppPatt 9 scope) patts
                                                      in ppCId f <+> hsep ds <+> char '=' <+> ppExpr 0 scope res | Equ patts res <- eqs]
 ppFun f (t,_,Nothing)  = text "data" <+> ppCId f <+> colon <+> ppType 0 [] t