haskell-src-exts-0.4.2: Language/Haskell/Exts/ParseUtils.hs
-- #hide
-----------------------------------------------------------------------------
-- |
-- Module : Language.Haskell.Exts.ParseUtils
-- Original : Language.Haskell.ParseUtils
-- Copyright : (c) Niklas Broberg 2004,
-- (c) The GHC Team, 1997-2000
-- License : BSD-style (see the file LICENSE.txt)
--
-- Maintainer : Niklas Broberg, d00nibro@dtek.chalmers.se
-- Stability : experimental
-- Portability : portable
--
-- Utilities for the Haskell-exts parser.
--
-----------------------------------------------------------------------------
module Language.Haskell.Exts.ParseUtils (
splitTyConApp -- Type -> P (Name,[Type])
, mkRecConstrOrUpdate -- Exp -> [FieldUpdate] -> P S.Exp
, checkPrec -- Integer -> P Int
, checkContext -- Type -> P Context
, checkAssertion -- Type -> P Asst
, checkDataHeader -- Type -> P (Context,Name,[Name])
, checkClassHeader -- Type -> P (Context,Name,[Name])
, checkInstHeader -- Type -> P (Context,QName,[Type])
, checkPattern -- PExp -> P Pat
, checkExpr -- PExp -> P Exp
-- , checkStmt -- Stmt -> P Stmt
, checkValDef -- SrcLoc -> S.Exp -> Rhs -> [Decl] -> P Decl
, checkClassBody -- [ClassDecl] -> P [ClassDecl]
, checkInstBody -- [InstDecl] -> P [InstDecl]
, checkUnQual -- QName -> P Name
, checkRevDecls -- [Decl] -> P [Decl]
, checkRevClsDecls -- [ClassDecl] -> P [ClassDecl]
, checkRevInstDecls -- [InstDecl] -> P [InstDecl]
, checkDataOrNew -- DataOrNew -> [Decl] -> P ()
, checkSimpleType -- Type -> P ()
, getGConName -- S.Exp -> P QName
, mkTyForall -- Maybe [Name] -> Context -> Type -> Type
-- HaRP
, checkRPattern -- PExp -> P RPat
-- Hsx
, checkEqNames -- XName -> XName -> P XName
, mkPageModule -- S.Exp -> P Module
, mkPage -- Module -> SrcLoc -> S.Exp -> P Module
, mkDVar -- [String] -> String
, mkDVarExpr -- [String] -> ParseExp
-- Parsed expressions
, PExp(..), PFieldUpdate(..), ParseXAttr(..)
, p_unit_con -- PExp
, p_tuple_con -- Int -> PExp
) where
import Language.Haskell.Exts.Syntax hiding ( Exp(..), FieldUpdate(..), XAttr(..) )
import qualified Language.Haskell.Exts.Syntax as S ( Exp(..), FieldUpdate(..), XAttr(..) )
import Language.Haskell.Exts.ParseMonad
import Language.Haskell.Exts.Pretty
import Language.Haskell.Exts.Build
import Data.List (intersperse)
splitTyConApp :: Type -> P (Name,[Type])
splitTyConApp t0 = split t0 []
where
split :: Type -> [Type] -> P (Name,[Type])
split (TyApp t u) ts = split t (u:ts)
split (TyCon (UnQual t)) ts = return (t,ts)
split (TyInfix a op b) ts = split (TyCon op) (a:b:ts)
split _ _ = fail "Illegal data/newtype declaration"
-----------------------------------------------------------------------------
-- Various Syntactic Checks
checkContext :: Type -> P Context
checkContext (TyTuple Boxed ts) =
mapM checkAssertion ts
checkContext t = do
c <- checkAssertion t
return [c]
-- Changed for multi-parameter type classes.
-- Further changed for implicit parameters.
checkAssertion :: Type -> P Asst
checkAssertion (TyPred p@(IParam _ _)) = return p
checkAssertion (TyPred p@(EqualP _ _)) = return p
checkAssertion t = checkAssertion' [] t
where checkAssertion' ts (TyCon c) = return $ ClassA c ts
checkAssertion' ts (TyApp a t) = checkAssertion' (t:ts) a
checkAssertion' ts (TyInfix a op b) = checkAssertion' (a:b:ts) (TyCon op)
checkAssertion' _ _ = fail "Illegal class assertion"
checkDataHeader :: Type -> P (Context,Name,[Name])
checkDataHeader (TyForall Nothing cs t) = do
(c,ts) <- checkSimple "data/newtype" t []
return (cs,c,ts)
checkDataHeader t = do
(c,ts) <- checkSimple "data/newtype" t []
return ([],c,ts)
checkClassHeader :: Type -> P (Context,Name,[Name])
checkClassHeader (TyForall Nothing cs t) = do
(c,ts) <- checkSimple "class" t []
return (cs,c,ts)
checkClassHeader t = do
(c,ts) <- checkSimple "class" t []
return ([],c,ts)
checkSimple :: String -> Type -> [Name] -> P (Name,[Name])
checkSimple kw (TyApp l (TyVar a)) xs = checkSimple kw l (a:xs)
checkSimple _ (TyInfix (TyVar a) (UnQual t) (TyVar b)) xs = return (t,a:b:xs)
checkSimple _kw (TyCon (UnQual t)) xs = return (t,xs)
checkSimple kw _ _ = fail ("Illegal " ++ kw ++ " declaration")
checkInstHeader :: Type -> P (Context,QName,[Type])
checkInstHeader (TyForall Nothing cs t) = do
(c,ts) <- checkInsts t []
return (cs,c,ts)
checkInstHeader t = do
(c,ts) <- checkInsts t []
return ([],c,ts)
checkInsts :: Type -> [Type] -> P ((QName,[Type]))
checkInsts (TyApp l t) ts = checkInsts l (t:ts)
checkInsts (TyCon c) ts = return (c,ts)
checkInsts _ _ = fail "Illegal instance declaration"
-----------------------------------------------------------------------------
-- Checking Patterns.
-- We parse patterns as expressions and check for valid patterns below,
-- converting the expression into a pattern at the same time.
checkPattern :: PExp -> P Pat
checkPattern e = checkPat e []
checkPat :: PExp -> [Pat] -> P Pat
checkPat (Con c) args = return (PApp c args)
checkPat (App f x) args = do
x <- checkPat x []
checkPat f (x:args)
checkPat e [] = case e of
Var (UnQual x) -> return (PVar x)
Lit l -> return (PLit l)
InfixApp l op r -> do
l <- checkPat l []
r <- checkPat r []
case op of
QConOp c -> return (PInfixApp l c r)
_ -> patFail ""
Tuple es -> do
ps <- mapM (\e -> checkPat e []) es
return (PTuple ps)
List es -> do
ps <- mapM checkRPattern es
return $ if all isStdPat ps
then PList $ map stripRP ps
else PRPat $ map fixRPOpPrec ps
where isStdPat :: RPat -> Bool
isStdPat (RPPat _) = True
isStdPat (RPAs _ p) = isStdPat p
isStdPat _ = False
stripRP :: RPat -> Pat
stripRP (RPPat p) = p
stripRP (RPAs n p) = PAsPat n (stripRP p)
stripRP _ = error "cannot strip RP wrapper if not all patterns are base"
Paren e -> do
p <- checkPat e []
return (PParen p)
AsPat n e -> do
p <- checkPat e []
return (PAsPat n p)
WildCard -> return PWildCard
IrrPat e -> do
p <- checkPat e []
return (PIrrPat p)
ViewPat e p -> do
e <- checkExpr e
p <- checkPat p []
return (PViewPat e p)
RecConstr c fs -> do
fs <- mapM checkPatField fs
return (PRec c fs)
NegApp (Lit l) -> return (PNeg (PLit l))
ExpTypeSig s e t -> do
p <- checkPat e []
return (PatTypeSig s p t)
-- Hsx
XTag s n attrs mattr cs -> do
pattrs <- mapM checkPAttr attrs
pcs <- mapM (\c -> checkPat c []) cs
mpattr <- maybe (return Nothing)
(\e -> do p <- checkPat e []
return $ Just p)
mattr
let cps = mkChildrenPat pcs
return $ PXTag s n pattrs mpattr cps
XETag s n attrs mattr -> do
pattrs <- mapM checkPAttr attrs
mpattr <- maybe (return Nothing)
(\e -> do p <- checkPat e []
return $ Just p)
mattr
return $ PXETag s n pattrs mpattr
XPcdata pcdata -> return $ PXPcdata pcdata
XExpTag e -> do
p <- checkPat e []
return $ PXPatTag p
XRPats es -> do
rps <- mapM checkRPattern es
return (PXRPats $ map fixRPOpPrec rps)
e -> patFail $ show e
checkPat e _ = patFail $ show e
checkPatField :: PFieldUpdate -> P PatField
checkPatField (FieldUpdate n e) = do
p <- checkPat e []
return (PFieldPat n p)
checkPAttr :: ParseXAttr -> P PXAttr
checkPAttr (XAttr n v) = do p <- checkPat v []
return $ PXAttr n p
patFail :: String -> P a
patFail s = fail $ "Parse error in pattern: " ++ s
checkRPattern :: PExp -> P RPat
checkRPattern e = case e of
SeqRP es -> do
rps <- mapM checkRPattern es
return $ RPSeq rps
PostOp e op -> do
rpop <- checkRPatOp op
rp <- checkRPattern e
return $ RPOp rp rpop
GuardRP e gs -> do
rp <- checkPattern e
return $ RPGuard rp gs
EitherRP e1 e2 -> do
rp1 <- checkRPattern e1
rp2 <- checkRPattern e2
return $ RPEither rp1 rp2
CAsRP n e -> do
rp <- checkRPattern e
return $ RPCAs n rp
AsPat n e -> do
rp <- checkRPattern e
return $ RPAs n rp
Paren e -> do
rp <- checkRPattern e
return $ RPParen rp
_ -> do
p <- checkPattern e
return $ RPPat p
checkRPatOp :: QOp -> P RPatOp
checkRPatOp o@(QVarOp (UnQual (Symbol sym))) =
case sym of
"*" -> return RPStar
"*!" -> return RPStarG
"+" -> return RPPlus
"+!" -> return RPPlusG
"?" -> return RPOpt
"?!" -> return RPOptG
_ -> rpOpFail o
checkRPatOp o = rpOpFail o
rpOpFail sym = fail $ "Unrecognized regular pattern operator: " ++ show sym
fixRPOpPrec :: RPat -> RPat
fixRPOpPrec rp = case rp of
RPOp rp rpop -> fPrecOp rp (flip RPOp rpop)
RPEither rp1 rp2 -> RPEither (fixRPOpPrec rp1) (fixRPOpPrec rp2)
RPSeq rps -> RPSeq $ map fixRPOpPrec rps
RPCAs n rp -> RPCAs n $ fixRPOpPrec rp
RPAs n rp -> RPAs n $ fixRPOpPrec rp
RPParen rp -> RPParen $ fixRPOpPrec rp
_ -> rp
where fPrecOp :: RPat -> (RPat -> RPat) -> RPat
fPrecOp (RPOp rp rpop) f = fPrecOp rp (f . flip RPOp rpop)
fPrecOp (RPCAs n rp) f = fPrecAs rp f (RPCAs n)
fPrecOp (RPAs n rp) f = fPrecAs rp f (RPAs n)
fPrecOp rp f = f $ fixRPOpPrec rp
fPrecAs :: RPat -> (RPat -> RPat) -> (RPat -> RPat) -> RPat
fPrecAs (RPCAs n rp) f g = fPrecAs rp f (g . RPCAs n)
fPrecAs (RPAs n rp) f g = fPrecAs rp f (g . RPAs n)
fPrecAs rp f g = g . f $ fixRPOpPrec rp
mkChildrenPat :: [Pat] -> [Pat]
mkChildrenPat ps = mkCPAux ps []
where mkCPAux :: [Pat] -> [Pat] -> [Pat]
mkCPAux [] qs = reverse qs
mkCPAux (p:ps) qs = case p of
(PRPat rps) -> [mkCRP ps (reverse rps ++ map RPPat qs)]
_ -> mkCPAux ps (p:qs)
mkCRP :: [Pat] -> [RPat] -> Pat
mkCRP [] rps = PXRPats $ reverse rps
mkCRP (p:ps) rps = case p of
(PXRPats rqs) -> mkCRP ps (reverse rqs ++ rps)
_ -> mkCRP ps (RPPat p : rps)
-----------------------------------------------------------------------------
-- Check Expression Syntax
checkExpr :: PExp -> P S.Exp
checkExpr e = case e of
Var v -> return $ S.Var v
IPVar v -> return $ S.IPVar v
Con c -> return $ S.Con c
Lit l -> return $ S.Lit l
InfixApp e1 op e2 -> check2Exprs e1 e2 (flip S.InfixApp op)
App e1 e2 -> check2Exprs e1 e2 S.App
NegApp e -> check1Expr e S.NegApp
Lambda loc ps e -> check1Expr e (S.Lambda loc ps)
Let bs e -> check1Expr e (S.Let bs)
If e1 e2 e3 -> check3Exprs e1 e2 e3 S.If
Case e alts -> do
-- alts <- mapM checkAlt alts
e <- checkExpr e
return (S.Case e alts)
Do stmts -> do
-- stmts <- mapM checkStmt stmts
return (S.Do stmts)
MDo stmts -> do
-- stmts <- mapM checkStmt stmts
return (S.MDo stmts)
Tuple es -> checkManyExprs es S.Tuple
List es -> checkManyExprs es S.List
-- Since we don't parse things as left sections, we need to mangle them into that.
Paren e -> case e of
PostOp e1 op -> check1Expr e1 (flip S.LeftSection op)
_ -> check1Expr e S.Paren
RightSection op e -> check1Expr e (S.RightSection op)
RecConstr c fields -> do
fields <- mapM checkField fields
return (S.RecConstr c fields)
RecUpdate e fields -> do
fields <- mapM checkField fields
e <- checkExpr e
return (S.RecUpdate e fields)
EnumFrom e -> check1Expr e S.EnumFrom
EnumFromTo e1 e2 -> check2Exprs e1 e2 S.EnumFromTo
EnumFromThen e1 e2 -> check2Exprs e1 e2 S.EnumFromThen
EnumFromThenTo e1 e2 e3 -> check3Exprs e1 e2 e3 S.EnumFromThenTo
ListComp e stmts -> do
--stmts <- mapM checkStmt stmts
e <- checkExpr e
return (S.ListComp e stmts)
ExpTypeSig loc e ty -> do
e <- checkExpr e
return (S.ExpTypeSig loc e ty)
--Template Haskell
BracketExp e -> return $ S.BracketExp e
SpliceExp e -> return $ S.SpliceExp e
TypQuote q -> return $ S.TypQuote q
VarQuote q -> return $ S.VarQuote q
-- Hsx
XTag s n attrs mattr cs -> do attrs <- mapM checkAttr attrs
cs <- mapM checkExpr cs
mattr <- maybe (return Nothing)
(\e -> checkExpr e >>= return . Just)
mattr
return $ S.XTag s n attrs mattr cs
XETag s n attrs mattr -> do attrs <- mapM checkAttr attrs
mattr <- maybe (return Nothing)
(\e -> checkExpr e >>= return . Just)
mattr
return $ S.XETag s n attrs mattr
XPcdata p -> return $ S.XPcdata p
XExpTag e -> do e <- checkExpr e
return $ S.XExpTag e
_ -> fail $ "Parse error in expression: " ++ show e
checkAttr :: ParseXAttr -> P S.XAttr
checkAttr (XAttr n v) = do v <- checkExpr v
return $ S.XAttr n v
-- type signature for polymorphic recursion!!
check1Expr :: PExp -> (S.Exp -> a) -> P a
check1Expr e1 f = do
e1 <- checkExpr e1
return (f e1)
check2Exprs :: PExp -> PExp -> (S.Exp -> S.Exp -> a) -> P a
check2Exprs e1 e2 f = do
e1 <- checkExpr e1
e2 <- checkExpr e2
return (f e1 e2)
check3Exprs :: PExp -> PExp -> PExp -> (S.Exp -> S.Exp -> S.Exp -> a) -> P a
check3Exprs e1 e2 e3 f = do
e1 <- checkExpr e1
e2 <- checkExpr e2
e3 <- checkExpr e3
return (f e1 e2 e3)
checkManyExprs :: [PExp] -> ([S.Exp] -> a) -> P a
checkManyExprs es f = do
es <- mapM checkExpr es
return (f es)
{-
checkAlt :: Alt -> P Alt
checkAlt (Alt loc p galts bs) = do
galts <- checkGAlts galts
return (Alt loc p galts bs)
checkGAlts :: GuardedAlts -> P GuardedAlts
checkGAlts (UnGuardedAlt e) = check1Expr e UnGuardedAlt
checkGAlts (GuardedAlts galts) = do
galts <- mapM checkGAlt galts
return (GuardedAlts galts)
checkGAlt :: GuardedAlt -> P GuardedAlt
checkGAlt (GuardedAlt loc g e) = check1Expr e (GuardedAlt loc g)
checkStmt :: Stmt -> P Stmt
checkStmt (Generator loc p e) = check1Expr e (Generator loc p)
checkStmt (Qualifier e) = check1Expr e Qualifier
checkStmt s@(LetStmt _) = return s
-}
checkField :: PFieldUpdate -> P S.FieldUpdate
checkField (FieldUpdate n e) = check1Expr e (S.FieldUpdate n)
getGConName :: S.Exp -> P QName
getGConName (S.Con n) = return n
getGConName (S.List []) = return list_cons_name
getGConName _ = fail "Expression in reification is not a name"
-----------------------------------------------------------------------------
-- Check Equation Syntax
checkValDef :: SrcLoc -> PExp -> Rhs -> Binds -> P Decl
checkValDef srcloc lhs rhs whereBinds =
case isFunLhs lhs [] of
Just (f,es) -> do
ps <- mapM checkPattern es
return (FunBind [Match srcloc f ps rhs whereBinds])
Nothing -> do
lhs <- checkPattern lhs
return (PatBind srcloc lhs rhs whereBinds)
-- A variable binding is parsed as an PatBind.
isFunLhs :: PExp -> [PExp] -> Maybe (Name, [PExp])
isFunLhs (InfixApp l (QVarOp (UnQual op)) r) es = Just (op, l:r:es)
isFunLhs (App (Var (UnQual f)) e) es = Just (f, e:es)
isFunLhs (App (Paren f) e) es = isFunLhs f (e:es)
isFunLhs (App f e) es = isFunLhs f (e:es)
isFunLhs _ _ = Nothing
-----------------------------------------------------------------------------
-- In a class or instance body, a pattern binding must be of a variable.
checkClassBody :: [ClassDecl] -> P [ClassDecl]
checkClassBody decls = do
mapM_ checkClassMethodDef decls
return decls
where checkClassMethodDef (ClsDecl decl) = checkMethodDef decl
checkClassMethodDef _ = return ()
checkInstBody :: [InstDecl] -> P [InstDecl]
checkInstBody decls = do
mapM_ checkInstMethodDef decls
return decls
where checkInstMethodDef (InsDecl decl) = checkMethodDef decl
checkInstMethodDef _ = return ()
checkMethodDef :: Decl -> P ()
checkMethodDef (PatBind _ (PVar _) _ _) = return ()
checkMethodDef (PatBind loc _ _ _) =
fail "illegal method definition" `atSrcLoc` loc
checkMethodDef _ = return ()
-----------------------------------------------------------------------------
-- Check that an identifier or symbol is unqualified.
-- For occasions when doing this in the grammar would cause conflicts.
checkUnQual :: QName -> P Name
checkUnQual (Qual _ _) = fail "Illegal qualified name"
checkUnQual (UnQual n) = return n
checkUnQual (Special _) = fail "Illegal special name"
-----------------------------------------------------------------------------
-- Check that two xml tag names are equal
-- Could use Eq directly, but I am not sure whether <dom:name>...</name>
-- would be valid, in that case Eq won't work. TODO
checkEqNames :: XName -> XName -> P XName
checkEqNames n@(XName n1) (XName n2)
| n1 == n2 = return n
| otherwise = fail "names in matching xml tags are not equal"
checkEqNames n@(XDomName d1 n1) (XDomName d2 n2)
| n1 == n2 && d1 == d2 = return n
| otherwise = fail "names in matching xml tags are not equal"
checkEqNames _ _ = fail "names in matching xml tags are not equal"
-----------------------------------------------------------------------------
-- Miscellaneous utilities
checkPrec :: Integer -> P Int
checkPrec i | 0 <= i && i <= 9 = return (fromInteger i)
checkPrec i | otherwise = fail ("Illegal precedence " ++ show i)
mkRecConstrOrUpdate :: PExp -> [PFieldUpdate] -> P PExp
mkRecConstrOrUpdate (Con c) fs = return (RecConstr c fs)
mkRecConstrOrUpdate e fs@(_:_) = return (RecUpdate e fs)
mkRecConstrOrUpdate _ _ = fail "Empty record update"
-----------------------------------------------------------------------------
-- Reverse a list of declarations, merging adjacent FunBinds of the
-- same name and checking that their arities match.
checkRevDecls :: [Decl] -> P [Decl]
checkRevDecls = mergeFunBinds []
where
mergeFunBinds revDs [] = return revDs
mergeFunBinds revDs (FunBind ms1@(Match _ name ps _ _:_):ds1) =
mergeMatches ms1 ds1
where
arity = length ps
mergeMatches ms' (FunBind ms@(Match loc name' ps' _ _:_):ds)
| name' == name =
if length ps' /= arity
then fail ("arity mismatch for '" ++ prettyPrint name ++ "'")
`atSrcLoc` loc
else mergeMatches (ms++ms') ds
mergeMatches ms' ds = mergeFunBinds (FunBind ms':revDs) ds
mergeFunBinds revDs (d:ds) = mergeFunBinds (d:revDs) ds
checkRevClsDecls :: [ClassDecl] -> P [ClassDecl]
checkRevClsDecls = mergeClsFunBinds []
where
mergeClsFunBinds revDs [] = return revDs
mergeClsFunBinds revDs (ClsDecl (FunBind ms1@(Match _ name ps _ _:_)):ds1) =
mergeMatches ms1 ds1
where
arity = length ps
mergeMatches ms' (ClsDecl (FunBind ms@(Match loc name' ps' _ _:_)):ds)
| name' == name =
if length ps' /= arity
then fail ("arity mismatch for '" ++ prettyPrint name ++ "'")
`atSrcLoc` loc
else mergeMatches (ms++ms') ds
mergeMatches ms' ds = mergeClsFunBinds (ClsDecl (FunBind ms'):revDs) ds
mergeClsFunBinds revDs (d:ds) = mergeClsFunBinds (d:revDs) ds
checkRevInstDecls :: [InstDecl] -> P [InstDecl]
checkRevInstDecls = mergeInstFunBinds []
where
mergeInstFunBinds revDs [] = return revDs
mergeInstFunBinds revDs (InsDecl (FunBind ms1@(Match _ name ps _ _:_)):ds1) =
mergeMatches ms1 ds1
where
arity = length ps
mergeMatches ms' (InsDecl (FunBind ms@(Match loc name' ps' _ _:_)):ds)
| name' == name =
if length ps' /= arity
then fail ("arity mismatch for '" ++ prettyPrint name ++ "'")
`atSrcLoc` loc
else mergeMatches (ms++ms') ds
mergeMatches ms' ds = mergeInstFunBinds (InsDecl (FunBind ms'):revDs) ds
mergeInstFunBinds revDs (d:ds) = mergeInstFunBinds (d:revDs) ds
----------------------------------------------------------------
-- Check that newtype declarations have
-- the right number (1) of constructors
checkDataOrNew :: DataOrNew -> [a] -> P ()
checkDataOrNew NewType [x] = return ()
checkDataOrNew DataType _ = return ()
checkDataOrNew _ _ = fail "newtype declaration must have exactly one constructor."
checkSimpleType :: Type -> P (Name, [Name])
checkSimpleType t = checkSimple "test" t []
---------------------------------------
-- Converting a complete page
pageFun :: SrcLoc -> S.Exp -> Decl
pageFun loc e = PatBind loc namePat rhs (BDecls [])
where namePat = PVar $ Ident "page"
rhs = UnGuardedRhs e
mkPage :: Module -> SrcLoc -> S.Exp -> P Module
mkPage (Module src md exps imps decls) loc xml = do
let page = pageFun loc xml
return $ Module src md exps imps (decls ++ [page])
mkPageModule :: S.Exp -> P Module
mkPageModule xml = do
do loc <- case xml of
S.XTag l _ _ _ _ -> return l
S.XETag l _ _ _ -> return l
_ -> fail "Will not happen since mkPageModule is only called on XML expressions"
mod <- getModuleName
return $ (Module
loc
(ModuleName mod)
(Just [EVar $ UnQual $ Ident "page"])
[]
[pageFun loc xml])
---------------------------------------
-- Handle dash-identifiers
mkDVar :: [String] -> String
mkDVar = concat . intersperse "-"
mkDVarExpr :: [String] -> PExp
mkDVarExpr = foldl1 (\x y -> InfixApp x (op $ sym "-") y) . map (Var . UnQual . name)
---------------------------------------
-- Combine adjacent for-alls.
--
-- A valid type must have one for-all at the top of the type, or of the fn arg types
mkTyForall :: Maybe [TyVarBind] -> Context -> Type -> Type
mkTyForall mtvs [] ty = mk_forall_ty mtvs ty
mkTyForall mtvs ctxt ty = TyForall mtvs ctxt ty
-- mk_forall_ty makes a pure for-all type (no context)
mk_forall_ty (Just []) ty = ty -- Explicit for-all with no tyvars
mk_forall_ty mtvs1 (TyForall mtvs2 ctxt ty) = mkTyForall (mtvs1 `plus` mtvs2) ctxt ty
mk_forall_ty mtvs1 ty = TyForall mtvs1 [] ty
mtvs1 `plus` Nothing = mtvs1
Nothing `plus` mtvs2 = mtvs2
(Just tvs1) `plus` (Just tvs2) = Just (tvs1 ++ tvs2)
---------------------------------------
-- Expressions as we parse them (and patters, and regular patterns)
data PExp
= Var QName -- ^ variable
| IPVar IPName -- ^ implicit parameter variable
| Con QName -- ^ data constructor
| Lit Literal -- ^ literal constant
| InfixApp PExp QOp PExp -- ^ infix application
| App PExp PExp -- ^ ordinary application
| NegApp PExp -- ^ negation expression @-@ /exp/
| Lambda SrcLoc [Pat] PExp -- ^ lambda expression
| Let Binds PExp -- ^ local declarations with @let@
| If PExp PExp PExp -- ^ @if@ /exp/ @then@ /exp/ @else@ /exp/
| Case PExp [Alt] -- ^ @case@ /exp/ @of@ /alts/
| Do [Stmt] -- ^ @do@-expression:
-- the last statement in the list
-- should be an expression.
| MDo [Stmt] -- ^ @mdo@-expression
| Tuple [PExp] -- ^ tuple expression
| List [PExp] -- ^ list expression
| Paren PExp -- ^ parenthesized expression
| RightSection QOp PExp -- ^ right section @(@/qop/ /exp/@)@
| RecConstr QName [PFieldUpdate]
-- ^ record construction expression
| RecUpdate PExp [PFieldUpdate]
-- ^ record update expression
| EnumFrom PExp -- ^ unbounded arithmetic sequence,
-- incrementing by 1
| EnumFromTo PExp PExp -- ^ bounded arithmetic sequence,
-- incrementing by 1
| EnumFromThen PExp PExp -- ^ unbounded arithmetic sequence,
-- with first two elements given
| EnumFromThenTo PExp PExp PExp
-- ^ bounded arithmetic sequence,
-- with first two elements given
| ListComp PExp [Stmt] -- ^ list comprehension
| ExpTypeSig SrcLoc PExp Type
-- ^ expression type signature
| AsPat Name PExp -- ^ patterns only
| WildCard -- ^ patterns only
| IrrPat PExp -- ^ patterns only
-- Post-ops for parsing left sections and regular patterns. Not to be left in the final tree.
| PostOp PExp QOp -- ^ post-ops
-- View patterns
| ViewPat PExp PExp -- ^ patterns only
-- HaRP
| SeqRP [PExp] -- ^ regular patterns only
| GuardRP PExp [Stmt] -- ^ regular patterns only
| EitherRP PExp PExp -- ^ regular patterns only
| CAsRP Name PExp -- ^ regular patterns only
-- Template Haskell
| VarQuote QName -- ^ 'x
| TypQuote QName -- ^ ''T
| BracketExp Bracket
| SpliceExp Splice
-- Hsx
| XTag SrcLoc XName [ParseXAttr] (Maybe PExp) [PExp]
| XETag SrcLoc XName [ParseXAttr] (Maybe PExp)
| XPcdata String
| XExpTag PExp
| XRPats [PExp]
deriving (Eq,Show)
data PFieldUpdate =
FieldUpdate QName PExp
deriving (Eq,Show)
data ParseXAttr = XAttr XName PExp
deriving (Eq,Show)
p_unit_con :: PExp
p_unit_con = Con unit_con_name
p_tuple_con :: Int -> PExp
p_tuple_con i = Con (tuple_con_name i)