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|
{-# OPTIONS_CYMAKE -Wno-incomplete-patterns -Wno-overlapping #-}
module CHR(CHR,Goal,(/\), (<=>), (==>), (|>), (\\),
true, fail, andCHR, allCHR, chrsToGoal,
toGoal1, toGoal2, toGoal3, toGoal4, toGoal5, toGoal6,
(.=.), (./=.), (.<=.), (.>=.), (.>.), (.<.),
nonvar, ground, anyPrim,
solveCHR, runCHR, runCHRwithTrace,
compileCHR, chr2curry
) where
import Char
import Findall ( rewriteSome )
import FlatCurry.Types
import FlatCurry.Files
import FlatCurry.Goodies
import FlatCurry.Pretty ( defaultOptions, ppTypeExp )
import List
import Pretty ( pretty )
import SetRBT
import Unsafe
import XML
import Prolog.Types
import Prolog.Show ( showPlClause, showPlGoals )
infix 5 .=., ./=., .<=., .>=., .>., .<.
infixr 4 /\
infix 3 <=>
infix 3 ==>
infix 2 \\
infix 1 |>
data CHR dom chr =
SimplRule [chr] [PrimConstraint dom] (Goal dom chr)
| PropaRule [chr] [PrimConstraint dom] (Goal dom chr)
| SimpaRule [chr] [chr] [PrimConstraint dom] (Goal dom chr)
(<=>) :: Goal dom chr -> Goal dom chr -> CHR dom chr
g1 <=> g2 =
if null (primsOfGoal g1)
then SimplRule (uchrOfGoal g1) [] g2
else error "Rule with primitive constraint on the left-hand side!"
(==>) :: Goal dom chr -> Goal dom chr -> CHR dom chr
g1 ==> g2 =
if null (primsOfGoal g1)
then PropaRule (uchrOfGoal g1) [] g2
else error "Rule with primitive constraint on the left-hand side!"
(\\) :: Goal dom chr -> CHR dom chr -> CHR dom chr
g1 \\ (SimplRule lchrs guard rcs)
| not (null (primsOfGoal g1))
= error "Simpagation rule with primitive kept constraints!"
| null keptcs
= SimplRule lchrs guard rcs
| null lchrs
= PropaRule keptcs guard rcs
| otherwise = SimpaRule keptcs lchrs guard rcs
where
keptcs = uchrOfGoal g1
(|>) :: CHR dom chr -> Goal dom chr -> CHR dom chr
rule |> g3 = attachGuard rule
where
attachGuard (SimplRule lcs guard rcs) =
if null (uchrOfGoal rcs)
then SimplRule lcs (guard ++ primsOfGoal rcs) g3
else error "Rule contains a guard with non-primitive constraints!"
attachGuard (PropaRule lcs guard rcs) =
if null (uchrOfGoal rcs)
then PropaRule lcs (guard ++ primsOfGoal rcs) g3
else error "Rule contains a guard with non-primitive constraints!"
attachGuard (SimpaRule h1 h2 guard rcs) =
if null (uchrOfGoal rcs)
then SimpaRule h1 h2 (guard ++ primsOfGoal rcs) g3
else error "Rule contains a guard with non-primitive constraints!"
data CHRconstr dom chr = PrimCHR (PrimConstraint dom) | UserCHR chr
data Goal dom chr = Goal [CHRconstr dom chr]
(/\) :: Goal dom chr -> Goal dom chr -> Goal dom chr
(/\) (Goal c1) (Goal c2) = Goal (c1 ++ c2)
true :: Goal dom chr
true = Goal []
fail :: Goal dom chr
fail = primToGoal Fail
andCHR :: [Goal dom chr] -> Goal dom chr
andCHR = foldr (/\) true
allCHR :: (a -> Goal dom chr) -> [a] -> Goal dom chr
allCHR fc = andCHR . map fc
uchrOfGoal :: Goal dom chr -> [chr]
uchrOfGoal (Goal cs) = concatMap uchr cs
where uchr (PrimCHR _) = []
uchr (UserCHR c) = [c]
primsOfGoal :: Goal dom chr -> [PrimConstraint dom]
primsOfGoal (Goal cs) = concatMap prim cs
where prim (PrimCHR c) = [c]
prim (UserCHR _) = []
chrsToGoal :: [chr] -> Goal dom chr
chrsToGoal cs = Goal (map UserCHR cs)
toGoal1 :: (a -> chr) -> a -> Goal dom chr
toGoal1 c x = Goal [UserCHR (c x)]
toGoal2 :: (a -> b -> chr) -> a -> b -> Goal dom chr
toGoal2 c x y = Goal [UserCHR (c x y)]
toGoal3 :: (a -> b -> c -> chr) -> a -> b -> c -> Goal dom chr
toGoal3 c x y z = Goal [UserCHR (c x y z)]
toGoal4 :: (a -> b -> c -> d -> chr)
-> a -> b -> c -> d -> Goal dom chr
toGoal4 con a b c d = Goal [UserCHR (con a b c d)]
toGoal5 :: (a -> b -> c -> d -> e -> chr)
-> a -> b -> c -> d -> e -> Goal dom chr
toGoal5 con a b c d e = Goal [UserCHR (con a b c d e)]
toGoal6 :: (a -> b -> c -> d -> e -> f -> chr)
-> a -> b -> c -> d -> e -> f -> Goal dom chr
toGoal6 con a b c d e f = Goal [UserCHR (con a b c d e f)]
data PrimConstraint a = Eq a a
| Neq a a
| Fail
| Compare (a -> a -> Bool) a a
| Ground a
| Nonvar a
| AnyPrim (() -> Bool)
primToGoal :: PrimConstraint dom -> Goal dom chr
primToGoal pc = Goal [PrimCHR pc]
(.=.) :: dom -> dom -> Goal dom chr
x .=. y = primToGoal (Eq x y)
(./=.) :: dom -> dom -> Goal dom chr
x ./=. y = primToGoal (Neq x y)
(.<=.) :: dom -> dom -> Goal dom chr
x .<=. y = primToGoal (Compare (<=) x y)
(.>=.) :: dom -> dom -> Goal dom chr
x .>=. y = primToGoal (Compare (>=) x y)
(.<.) :: dom -> dom -> Goal dom chr
x .<. y = primToGoal (Compare (<) x y)
(.>.) :: dom -> dom -> Goal dom chr
x .>. y = primToGoal (Compare (>) x y)
ground :: dom -> Goal dom chr
ground x = primToGoal (Ground x)
nonvar :: dom -> Goal dom chr
nonvar x = primToGoal (Nonvar x)
anyPrim :: (() -> Bool) -> Goal dom chr
anyPrim cf = primToGoal (AnyPrim cf)
evalPrimCHR :: PrimConstraint _ -> Bool
evalPrimCHR (Eq x y) = x=:=y
evalPrimCHR (Neq x y) = (x==y) =:= False
evalPrimCHR Fail = failed
evalPrimCHR (Compare cmp x y) = (cmp x y) =:= True
evalPrimCHR (Nonvar x) = Unsafe.isVar x =:= False
evalPrimCHR (Ground x) = Unsafe.isGround x =:= True
evalPrimCHR (AnyPrim cf) = cf ()
solveCHR :: [[dom] -> CHR dom chr] -> Goal dom chr -> Bool
solveCHR prules goal =
let residual = runCHR prules goal
in if null residual
then True
else trace ("WARNING: residual CHR constraints: "++show residual++"\n")
True
type History = SetRBT ([Int],Int)
emptyHistory :: SetRBT a
emptyHistory = emptySetRBT (<=)
extendHistory :: a -> SetRBT a -> SetRBT a
extendHistory = insertRBT
inHistory :: a -> SetRBT a -> Bool
inHistory = elemRBT
runCHR :: [[dom] -> CHR dom chr] -> Goal dom chr -> [chr]
runCHR prules goal = evalCHR False prules goal
runCHRwithTrace :: [[dom] -> CHR dom chr] -> Goal dom chr -> [chr]
runCHRwithTrace prules goal = evalCHR True prules goal
evalCHR :: Bool -> [[dom] -> CHR dom chr] -> Goal dom chr -> [chr]
evalCHR withtrace urules (Goal goal)
| evalConstr gidx emptyHistory chrgoal [] result
= map snd result
where
tracing s = if withtrace then trace s else id
result free
rules = zip [1..] urules
(gidx,chrgoal) = numberCHR 0 goal
solvePrims = all evalPrimCHR
evalConstr gi hist gl cstore finalcs = tracing (showAnyTerm (gl,cstore)) $
evalC gl cstore finalcs
where
evalC [] cs rcs = cs =:= rcs
evalC (PrimCHR pc : gs) cs rcs =
tracing ("Evaluate primitive: " ++ showAnyTerm pc) $
evalPrimCHR pc & evalConstr gi hist (map UserCHR cs ++ gs) [] rcs
evalC (UserCHR c : gs) cs rcs =
(normalForm c)
`seq` tryRules gi hist rules c gs cs rcs
tryRules gi hs [] c gs cs rcs =
maybe (tracing "Suspend constraint" $
evalConstr gi hs gs (c:cs) rcs)
(\ (pc,mgs) -> tracing ("Evaluate primitive: " ++ showAnyTerm pc) $
evalPrimCHR pc &
evalConstr gi hs (map UserCHR (c:cs) ++ mgs) [] rcs)
(extractPrim gs)
tryRules gi hist ((ri,r) : rs) c gs cs rcs =
maybe (tryRules gi hist rs c gs cs rcs)
(\ (newcs,newgs,remcs,is) ->
if (is,ri) `inHistory` hist
then tryRules gi hist rs c gs cs rcs
else
let (gj,inewcs) = numberCHR gi newcs
in tracing ("Apply rule " ++ show ri) $
evalConstr gj
(if null is then hist
else extendHistory (is,ri) hist)
(inewcs++newgs)
remcs rcs)
(rewriteSome (applyRule (r unknown) c gs cs))
applyRule (SimplRule lchrs guard (Goal rchrs)) (_,c) gs cs
| deleteSome c lchrs =:= lhs & findDelete lhs cs =:= (delcs,remcs)
&> solvePrims guard
= (rchrs,gs,remcs,[]) where lhs,delcs,remcs free
applyRule (PropaRule lchrs guard (Goal rchrs)) (i,c) gs cs
| deleteSome c lchrs =:= lhs & findDelete lhs cs =:= (delcs,_)
&> solvePrims guard
= (rchrs, UserCHR (i,c) : gs, cs, i : map fst delcs) where lhs,delcs free
applyRule (SimpaRule kept lchrs guard (Goal rchrs)) (_,c) gs cs
| deleteSome c lchrs =:= lhs & findDelete (kept++lhs) cs =:= (delcs,remcs)
&> solvePrims guard
= (rchrs, gs, take (length kept) delcs ++ remcs, [])
where lhs,delcs,remcs free
applyRule (SimpaRule kept lchrs guard (Goal rchrs)) (i,c) gs cs
| deleteSome c kept =:= kc & findDelete (kc++lchrs) cs =:= (delcs,remcs)
&> solvePrims guard
= (rchrs, UserCHR (i,c) : gs, take (length kc) delcs ++ remcs, [])
where kc,delcs,remcs free
findDelete :: [a] -> [(Int,a)] -> ([(Int,a)],[(Int,a)])
findDelete [] cs = ([],cs)
findDelete (x:xs) cs = let (z,ds) = del x cs
(zs,es) = findDelete xs ds
in (z:zs,es)
where
del e (z:zs) | e=:=snd z = (z,zs)
del e (z:zs) = let (y,ys) = del e zs in (y, z:ys)
deleteSome :: a -> [a] -> [a]
deleteSome e (z:zs) | e=:=z = zs
deleteSome e (z:zs) = z : deleteSome e zs
extractPrim :: [CHRconstr dom chr]
-> Maybe (PrimConstraint dom, [CHRconstr dom chr])
[] = Nothing
extractPrim (PrimCHR pc : cs) = Just (pc, cs)
extractPrim (UserCHR c : cs) =
maybe Nothing
(\ (pc,rcs) -> Just (pc, UserCHR c : rcs))
(extractPrim cs)
numberCHR :: Int -> [CHRconstr dom chr] -> (Int, [CHRconstr dom (Int,chr)])
numberCHR i [] = (i,[])
numberCHR i (PrimCHR pc : cs) =
let (j,ics) = numberCHR i cs in (j, PrimCHR pc : ics)
numberCHR i (UserCHR c : cs) =
let (j,ics) = numberCHR (i+1) cs in (j, UserCHR (i,c) : ics)
compileCHR :: String -> [[dom] -> CHR dom chr] -> IO ()
compileCHR currymod rules
| null rids = putStrLn "No CHR rules to compile."
| any (/=sourcemodname) (map fst rids)
= error "Cannot compile CHR rules from different modules!"
| otherwise = compileRules sourcemodname currymod (map snd rids)
where
rids = map ruleId rules
sourcemodname = fst (head rids)
ruleId :: ([dom] -> CHR dom chr) -> QName
ruleId rule =
let rcallstring = showAnyQExpression rule
qid = takeWhile (not . isSpace) (drop (length "(partcall 1 ") rcallstring)
(mname,rname) = break (=='.') qid
in (mname, tail rname)
compileRules :: String -> String -> [String] -> IO ()
compileRules modname chrmodname rids = do
(Prog _ _ _ fdecls opdecls) <- readFlatCurry modname
let pmodname = chrmodname++"_prim"
getftype = getFuncType fdecls
rdefs = filter (\ (Func fname _ _ _ _) -> snd fname `elem` rids) fdecls
(chrs,_) = unzip (map (compileRule getftype []) (map funcRule rdefs))
allchrs = nub (concat chrs)
(_,trules) = unzip (map (compileRule getftype allchrs)
(map funcRule rdefs))
allchrtypes = zip allchrs (map getftype (map fst allchrs))
curryprog = showCHRModule modname chrmodname opdecls allchrtypes
prologprog = unlines $
map showPlClause
([PlDirective
[PlLit "module"
[PlAtom pmodname,
plList (map (\ (qcname,carity)->
PlStruct "/" [PlAtom (showCName ("prim_"++snd qcname)),
PlInt (carity+1)])
allchrs)]],
PlDirective [PlLit "use_module"
[PlStruct "library" [PlAtom "chr"]]]] ++
map (\ (p,a) ->
PlDirective
[PlLit "chr_constraint"
[PlStruct "/" [PlAtom (showQName p), PlInt a]]])
allchrs) ++
["","% CHR rules:"] ++ trules ++ ["","% Curry/Prolog interface:"] ++
map (showPlClause . chrPrologPrimDefinition) allchrs ++
["","% Auxiliary predicates:",
"sunif(X,Y) :- user:evalToken(E), user:hnf('Prelude.=:='(X,Y),_,E,_).",
"eval(X) :- user:evalToken(E), user:hnf(X,_,E,_)."]
writeFile (chrmodname++".curry") curryprog
writeXmlFileWithParams (chrmodname++".prim_c2p")
[DtdUrl "http://www.informatik.uni-kiel.de/~pakcs/primitives.dtd"]
(constraints2xml pmodname allchrs)
writeFile (pmodname++".pl") prologprog
putStrLn $ "Curry interface to CHR(Prolog) written to "++chrmodname++".curry"
getFuncType :: [FuncDecl] -> (String,String) -> TypeExpr
getFuncType fdecls qfname =
maybe (error $ showQName qfname ++ " not found!")
funcType
(find (\ (Func qf _ _ _ _) -> qf == qfname) fdecls)
chrPrologPrimDefinition :: (QName,Int) -> PlClause
chrPrologPrimDefinition (qcname,carity) =
PlClause
(showCName ("prim_"++snd qcname))
(map PlVar (map (\i->"X"++show i) [1..carity] ++ ["R"]))
[PlLit (showQName qcname) (map (\i->PlVar ("X"++show i)) [1..carity]),
PlLit "=" [PlVar "R", PlAtom "Prelude.True"]]
showCHRModule :: String -> String -> [OpDecl] ->
[((QName,Int),TypeExpr)] -> String
showCHRModule orgmod chrmod opdecls constraints = unlines $
["module "++chrmod++exports++" where","",
"import qualified CHR(chr2curry)",
"import CHRcompiled",
"import qualified "++orgmod,""] ++
map showOpDecl chropdecls ++ [""] ++
map showCurryConstraint constraints
where
exports = "(module CHRcompiled" ++
concatMap (',':) (map (showCName . snd) chrqnames) ++ ")"
chrqnames = map (fst . fst) constraints
chropdecls = filter (\ (Op qop _ _) -> qop `elem` chrqnames) opdecls
showOpDecl :: OpDecl -> String
showOpDecl (Op op fixity prec) = unwords [showFixity fixity,show prec,showOp op]
where
showFixity InfixOp = "infix"
showFixity InfixlOp = "infixl"
showFixity InfixrOp = "infixr"
showOp (_,on) = if isAlpha (head on) then '`':on++"`" else on
showCurryConstraint :: ((QName,Int),TypeExpr) -> String
showCurryConstraint (((_,cname),carity),ctype) =
let cargtypes = argTypes carity ctype in
showCName cname ++" :: "++ concatMap (++" -> ") cargtypes
++"Goal "++ showCurryType (resultType carity ctype) ++"\n"++
showCName cname ++ concatMap (\i->" x"++show i) [1..carity] ++ " = Goal " ++
take carity (repeat '(') ++
showCName ("prim_"++cname) ++
concatMap (\i->" $!! x"++show i++")") [1..carity] ++ "\n\n" ++
showCName ("prim_"++cname) ++ " :: " ++
concatMap (++" -> ") cargtypes ++ "Bool\n" ++
showCName ("prim_"++cname) ++ " external\n"
where
resultType arity tp =
if arity==0 then let TCons _ [_,chrtype] = tp
in chrtype
else let FuncType _ rtype = tp
in resultType (arity-1) rtype
argTypes arity ftype = if arity==0 then [] else
let FuncType atype rtype = ftype
in showCurryType atype : argTypes (arity-1) rtype
constraints2xml :: String -> [(QName,Int)] -> XmlExp
constraints2xml prologmod constraints =
xml "primitives" (map constraint2xml constraints)
where
constraint2xml ((_,cname),carity) =
XElem "primitive" [("name",showCName ("prim_"++cname)),
("arity",show carity)]
[xml "library" [xtxt prologmod],
xml "entry" [xtxt (showCName ("prim_"++cname))]]
compileRule :: (QName -> TypeExpr) -> [(QName,Int)] -> Rule
-> ([(QName,Int)],String)
compileRule getftype chrs (Rule _ rhs) =
let (_,rchrs,trule) = exp2CHR 100 (firstBranch rhs)
in (rchrs, trule ++ ".")
where
exp2CHR i exp@(Comb FuncCall qf [a1,a2])
| qf == (chrMod,"<=>") = let (j, chrs1,tgoal1) = transGoal i a1
(k,_,tgoal2) = transGoal j a2
in (k, chrs1, sg tgoal1 ++" <=> "++ sg tgoal2)
| qf == (chrMod,"==>") = let (j,chrs1,tgoal1) = transGoal i a1
(k,_,tgoal2) = transGoal j a2
in (k, chrs1, sg tgoal1 ++" ==> "++ sg tgoal2)
| qf == (chrMod,"\\\\") = let (j,chrs1,tgoal1) = transGoal i a1
(k,chrs2,trule2) = exp2CHR j a2
in (k, chrs1++chrs2, sg tgoal1 ++" \\ "++ trule2)
| qf == (chrMod,"|>") = let (j,chrs1,trule1) = exp2CHR i a1
(k,_,tgoal2) = transGoal j a2
in (k, chrs1, trule1 ++" | "++ sg tgoal2)
| otherwise = error ("Cannot translate CHR rule: " ++ show exp)
where sg = showPlGoals
transGoal i exp = case reduceApply exp of
Comb FuncCall qf args -> if fst qf == chrMod then transCHRPred i qf args
else transUserPred i qf args
_ -> error ("Cannot translate CHR literal: " ++ show exp)
transCHRPred i (_,cname) args
| cname=="/\\" =
let (j,chrs1,tgoal1) = transGoal i (args!!0)
(k,chrs2,tgoal2) = transGoal j (args!!1)
in (k, chrs1++chrs2, tgoal1 ++ tgoal2)
| cname=="nonvar" = (i, [], [PlLit "nonvar" [transArg (args!!0)]])
| cname=="ground" = (i, [], [PlLit "ground" [transArg (args!!0)]])
| cname=="true" = (i, [], [PlLit "true" []])
| cname=="fail" = (i, [], [PlLit "fail" []])
| otherwise = maybe (error $ "Illegal CHR constraint: CHR."++cname)
(\chr2pl -> (i, [], [chr2pl (map transArg args)]))
(lookup cname chrPrims)
transUserPred i qf args =
let (j,plits,plit) = flattenLiteral i qf args
fplit = if qf `elem` map fst chrs
then plit
else if isCHRType (getftype qf)
then let PlLit pn pargs = plit
in PlLit "eval" [PlStruct "CHR.chr2curry"
[PlStruct pn pargs]]
else error ("Operation '"++snd qf++
"' is not a CHR constraint!")
in (j, [(qf,length args)], plits ++ [fplit])
isCHRType :: TypeExpr -> Bool
isCHRType texp = case texp of
FuncType _ rt -> isCHRType rt
TCons qtc _ -> qtc == (chrMod,"Goal")
_ -> False
firstBranch :: Expr -> Expr
firstBranch exp = case exp of
Case _ _ (Branch _ bexp : brs) ->
if null brs
then firstBranch bexp
else error ("CHR rule with more than one branch: "++show exp)
Free _ fexp -> firstBranch fexp
_ -> exp
reduceApply :: Expr -> Expr
reduceApply exp = case exp of
Comb FuncCall ("Prelude","apply") [a1,a2] ->
let ra1 = reduceApply a1 in
case ra1 of
Comb FuncCall qf fargs -> Comb FuncCall qf (fargs++[a2])
_ -> Comb FuncCall ("Prelude","apply") [ra1,a2]
_ -> exp
chrPrims :: [(String,[PlTerm] -> PlGoal)]
chrPrims =
[(".=.", \args -> PlLit "sunif" args),
("./=.",\args -> PlLit "sunif" [PlStruct "Prelude.==" args, pfalse]),
(".>=.",\args -> PlLit "sunif" [PlStruct "Prelude.>=" args, ptrue]),
(".<=.",\args -> PlLit "sunif" [PlStruct "Prelude.<=" args, ptrue]),
(".>.", \args -> PlLit "sunif" [PlStruct "Prelude.>" args, ptrue]),
(".<.", \args -> PlLit "sunif" [PlStruct "Prelude.<" args, ptrue])]
where ptrue = PlAtom "Prelude.True"
pfalse = PlAtom "Prelude.False"
transArg :: Expr -> PlTerm
transArg e = case e of
Lit (Intc i) -> PlInt i
Lit (Floatc f) -> PlFloat f
Var i -> PlVar ('X' : show i)
Comb FuncCall qf args -> PlStruct (showQName qf) (map transArg args)
Comb ConsCall qf args -> PlStruct (transCName qf) (map transArg args)
_ -> error ("Not yet translatable argument: "++show e)
where
transCName qf | qf == ("Prelude","[]") = "[]"
| qf == ("Prelude",":") = "."
| otherwise = showQName qf
flattenLiteral :: Int -> QName -> [Expr] -> (Int,[PlGoal],PlGoal)
flattenLiteral i qf args =
let (j,flits,fargs) = flattenArgs i args
in (j, flits, PlLit (showQName qf) (map transArg fargs))
flattenArgs :: Int -> [Expr] -> (Int,[PlGoal],[Expr])
flattenArgs i [] = (i,[],[])
flattenArgs i (arg:args) =
if funcArg arg
then let (j,flits,fargs) = flattenArgs (i+1) args
in (j, PlLit "sunif" [PlVar ("X"++show i), transArg arg] : flits,
Var i:fargs)
else let (j,flits,fargs) = flattenArgs i args
in (j, flits, arg : fargs)
where
funcArg e = case e of
Lit _ -> False
Var _ -> False
Comb ConsCall _ cargs -> any funcArg cargs
_ -> True
showQName :: QName -> String
showQName (mname,fname) = mname++"."++fname
showCName :: String -> String
showCName s
| all (\c -> isAlphaNum c || c=='_') s = s
| isAlpha (head s) = concatMap (\c -> if isAlphaNum c || c=='_'
then [c]
else 'X':show (ord c))
s
| otherwise = "("++s++")"
chrMod :: String
chrMod = "CHR"
chr2curry :: CHR.Goal dom chr -> Bool
chr2curry (CHR.Goal c) = case c of
[CHR.PrimCHR pc] -> CHR.evalPrimCHR pc
_ -> error "CHRcompiled.chr2curry: unexpected argument!"
showCurryType :: TypeExpr -> String
showCurryType te = '(' : pretty 78 (ppTypeExp defaultOptions te) ++ ")"
|