alms-0.4.11: src/Ppr.hs
-- | Pretty-printing
{-# LANGUAGE
PatternGuards,
QuasiQuotes,
TypeSynonymInstances
#-}
module Ppr (
pprTyApp,
-- * Re-exports
module PprClass,
module Prec
) where
import Meta.Quasi
import PprClass
import Prec
import Syntax
import Util
import qualified Syntax.Decl
import qualified Syntax.Expr
import qualified Syntax.Notable
import qualified Syntax.Patt
import qualified Loc
import Data.List (intersperse)
instance IsInfix (Type i) where
isInfix [$ty| ($_, $_) $lid:n |] = isOperator n
isInfix [$ty| $_ -[$_]> $_ |] = True
isInfix _ = False
-- | For printing infix expressions. Given a splitter function that
-- splits expressions into a left operand, operator name, and right
-- operand (if possible), and an expression to print, pretty-prints
-- the expression, but only if there is one level of infix to be
-- done.
pprInfix :: Ppr a =>
(a -> Maybe (a, String, Maybe a)) ->
a -> Maybe Doc
pprInfix inspect x0
| Just (x1, op, Nothing) <- inspect x0
, precOp op == Right precBang
= Just (prec precBang (text op <+> ppr x1))
| Just (_, op, Just _) <- inspect x0
, isOperator (lid op :: Lid Raw)
, p <- precOp op
, p /= Right precBang
= Just $
prec (id|||id $ p) $
fcat $ mapTail (nest 2) $ loop p empty x0
| otherwise
= Nothing
where
loop p suf x
| Just (x1, op, Just x2) <- inspect x
, precOp op == p
= case precOp op of
Left _ -> loop p (oper op) x1 ++ [ppr1 x2 <> suf]
Right _ -> ppr1 x1 <> oper op : loop p suf x2
loop _ suf x = [ ppr x <> suf ]
oper s = case s of
'@':_ -> text s
';':_ -> text s <> space
_ -> space <> text s <> space
instance Ppr (Type i) where
-- pprPrec p (TyFun q t1 t2)
ppr [$ty| $t1 -[$q]> $t2 |]
= prec precArr $
sep [ ppr1 t1,
pprArr (view q) <+> pprRight t2 ]
where pprArr (QeLit Qu) = text "->"
pprArr (QeLit Qa) = text "-o"
pprArr _ = text "-[" <> ppr0 q <> text "]>"
ppr t@[$ty| ($list:ts) $qlid:n |]
| Just doc <- pprInfix unfoldType t
= doc
| null ts = ppr n
| otherwise = prec precApp $ sep [ ppr ts, ppr n ]
-- debugging: <> text (show (ttId (unsafeCoerce tag :: TyTag)))
ppr [$ty| '$x |] = ppr x
ppr [$ty| $quant:qu '$x. $t |]
= prec precDot $
ppr qu <+>
fsep (map ppr1 tvs) <>
char '.'
>+> ppr body
where (tvs, body) = unfoldTyQu qu [$ty| $quant:qu '$x. $t |]
ppr [$ty| mu '$x. $t |]
= prec precDot $
text "mu" <+>
ppr1 x <>
char '.'
>+> ppr t
ppr [$ty| $anti:a |] = ppr a
unfoldType :: Type i -> Maybe (Type i, String, Maybe (Type i))
unfoldType [$ty| ($t1, $t2) $name:n |] = Just (t1, n, Just t2)
unfoldType [$ty| $t1 $name:n |] = Just (t1, n, Nothing)
unfoldType _ = Nothing
instance Ppr (TyPat i) where
ppr tp0 = case tp0 of
_ | Just doc <- pprInfix unfoldTyPat tp0
-> doc
N _ (TpVar tv var) -> pprParamV var tv
[$tpQ| ($list:tps) $qlid:ql |]
-> ppr tps <+> ppr ql
[$tpQ| $antiP:a |] -> ppr a
unfoldTyPat :: TyPat i -> Maybe (TyPat i, String, Maybe (TyPat i))
unfoldTyPat [$tpQ| ($t1, $t2) $name:n |] = Just (t1, n, Just t2)
unfoldTyPat [$tpQ| $t1 $name:n |] = Just (t1, n, Nothing)
unfoldTyPat _ = Nothing
instance Ppr (QExp i) where
ppr [$qeQ| $qlit:qu |] = ppr qu
ppr [$qeQ| $qvar:v |] = ppr (tvname v)
ppr [$qeQ| $qdisj:qes |] = case qes of
[] -> ppr Qu
[qe] -> ppr qe
_ -> prec precPlus $
fsep $
intersperse (text "\\/") $
map ppr1 qes
ppr [$qeQ| $qconj:qes |] = case qes of
[] -> ppr Qa
[qe] -> ppr qe
_ -> prec precStar $
hcat $
intersperse (text "/\\") $
map ppr1 qes
ppr [$qeQ| $anti:a |] = ppr a
instance Ppr (Prog i) where
ppr [$prQ| $list:ms |] = vcat (map ppr0 ms)
ppr [$prQ| $expr:e |] = ppr e
ppr [$prQ| $list:ms in $e |] = vcat (map ppr0 ms) $+$
(text "in" >+> ppr e)
instance Ppr (Decl i) where
ppr [$dc| let $x = $e |] = sep
[ text "let" <+> ppr x,
nest 2 $ equals <+> ppr e ]
ppr [$dc| let $x : $t = $e |] = sep
[ text "let" <+> ppr x,
nest 2 $ colon <+> ppr t,
nest 4 $ equals <+> ppr e ]
ppr [$dc| type $list:tds |] = pprTyDecs tds
ppr [$dc| abstype $list:ats0 with $list:ds end |] =
case ats0 of
[] ->
vcat [
text "abstype with",
nest 2 $ vcat (map ppr ds),
text "end"
]
at:ats ->
vcat [
vcat (text "abstype" <+> pprAbsTy at :
[ nest 4 $ text "and" <+> pprAbsTy ati | ati <- ats ])
<+> text "with",
nest 2 $ vcat (map ppr ds),
text "end"
]
ppr [$dc| open $b |] = pprModExp (text "open" <+>) b
ppr [$dc| module $uid:n : $s = $b |] = pprModExp add1 b where
add1 body = pprSigExp add2 s <+> equals <+> body
add2 body = text "module" <+> ppr n <+> colon <+> body
ppr [$dc| module $uid:n = $b |] = pprModExp add b where
add body = text "module" <+> ppr n <+> equals <+> body
ppr [$dc| module type $uid:n = $s |] = pprSigExp add s where
add body = text "module type" <+> ppr n <+> equals <+> body
ppr [$dc| local $list:d0 with $list:d1 end |] =
vcat [
text "local",
nest 2 (vcat (map ppr d0)),
text "with",
nest 2 (vcat (map ppr d1)),
text "end"
]
ppr [$dc| exception $uid:n of $opt:mt |] =
pprExcDec n mt
ppr [$dc| $anti:a |] = ppr a
pprTyDecs :: [TyDec i] -> Doc
pprTyDecs tds =
vcat $
mapHead (text "type" <+>) $
mapTail ((nest 1) . (text "and" <+>)) $
map ppr tds
pprExcDec :: Uid i -> Maybe (Type i) -> Doc
pprExcDec u Nothing =
text "exception" <+> ppr u
pprExcDec u (Just t) =
text "exception" <+> ppr u <+> text "of" <+> ppr t
instance Ppr (TyDec i) where
ppr td = case view td of
TdAbs n ps vs qs -> pprProtoV n vs ps >?> pprQuals qs
TdSyn n [(ps,t)] -> pprProto n ps >+> equals <+> ppr t
TdSyn n cs -> vcat [ char '|' <+> each ci | ci <- cs ]
where
each (ps, rhs) = pprProto n ps
>+> char '=' <+> ppr rhs
TdDat n ps alts -> pprProtoV n (repeat Invariant) ps
>?> pprAlternatives alts
TdAnti a -> ppr a
pprAbsTy :: AbsTy i -> Doc
pprAbsTy at = case view at of
AbsTy variances qual (N _ (TdDat name params alts)) ->
pprProtoV name variances params
>?> pprQuals qual
>?> pprAlternatives alts
AbsTy _ _ td -> ppr td -- shouldn't happen (yet)
AbsTyAnti a -> ppr a
pprProto :: Lid i -> [TyPat i] -> Doc
pprProto n ps = ppr (tpApp (J [] n) ps)
pprProtoV :: Lid i -> [Variance] -> [TyVar i] -> Doc
pprProtoV n vs tvs = pprProto n (zipWith tpVar tvs vs)
pprParamV :: Variance -> TyVar i -> Doc
pprParamV Invariant tv = ppr tv
pprParamV v tv = ppr v <> ppr tv
pprQuals :: QExp i -> Doc
pprQuals [$qeQ| U |] = empty
pprQuals qs = text ":" <+> pprPrec precApp qs
pprAlternatives :: [(Uid i, Maybe (Type i))] -> Doc
pprAlternatives [] = equals
pprAlternatives (a:as) = sep $
equals <+> alt a : [ char '|' <+> alt a' | a' <- as ]
where
alt (u, Nothing) = ppr u
alt (u, Just t) = ppr u <+> text "of" <+> pprPrec precDot t
pprModExp :: (Doc -> Doc) -> ModExp i -> Doc
pprModExp add modexp = case modexp of
[$me| $quid:n |] -> add (ppr n)
[$me| $quid:n $list:qls |] ->
add (ppr n) <+>
brackets (fsep (punctuate comma (map ppr qls)))
[$me| struct $list:ds end |] ->
add (text "struct")
$$ nest 2 (vcat (map ppr0 ds))
$$ text "end"
[$me| $me1 : $se2 |] ->
pprSigExp (pprModExp add me1 <+> colon <+>) se2
[$me| $anti:a |] -> add (ppr a)
pprSigExp :: (Doc -> Doc) -> SigExp i -> Doc
pprSigExp add se0 = body >+> withs where
(wts, se1) = unfoldSeWith se0
body = case se1 of
[$seQ| $quid:n |] -> add (ppr n)
[$seQ| $quid:n $list:qls |] ->
add (ppr n) <+>
brackets (fsep (punctuate comma (map ppr qls)))
[$seQ| sig $list:sgs end |] ->
add (text "sig")
$$ nest 2 (vcat (map ppr0 sgs))
$$ text "end"
[$seQ| $_ with type $list:_ $qlid:_ = $_ |] ->
error "BUG! can't happen in pprSigExp"
[$seQ| $anti:a |] -> add (ppr a)
withs =
atPrec 0 $ sep $
mapHead (text "with type" <+>) $
mapTail ((nest 6) . (text "and" <+>)) $
[ pprTyApp tc tvs <+> equals <+> ppr t
| (tc, tvs, t) <- wts ]
instance Ppr (SigItem i) where
ppr sg0 = case sg0 of
[$sgQ| val $lid:n : $t |] ->
text "val" <+> ppr n >+> colon <+> ppr t
[$sgQ| type $list:tds |] ->
pprTyDecs tds
[$sgQ| module $uid:u : $s |] ->
pprSigExp add s where
add body = text "module" <+> ppr u <+> colon <+> body
[$sgQ| module type $uid:u = $s |] ->
pprSigExp add s where
add body = text "module type" <+> ppr u <+> equals <+> body
[$sgQ| include $s |] ->
pprSigExp (text "include" <+>) s
[$sgQ| exception $uid:u of $opt:mt |] ->
pprExcDec u mt
[$sgQ| $anti:a |] ->
ppr a
instance Ppr (Expr i) where
ppr e0 = case e0 of
_ | Just doc <- pprInfix unfoldExpr e0
-> doc
[$ex| $id:x |] -> ppr x
[$ex| $lit:lt |] -> ppr lt
[$ex| if $ec then $et else $ef |] ->
prec precDot $
sep [ text "if" <+> ppr ec,
nest 2 $ text "then" <+> ppr0 et,
nest 2 $ text "else" <+> ppr ef ]
[$ex| $_; $_ |] ->
prec precDot $
sep (unfold e0)
where unfold [$ex| $e1; $e2 |] = ppr1 e1 <> semi : unfold e2
unfold e = [ ppr0 e ]
[$ex| let $x = $e1 in $e2 |] ->
pprLet (ppr x) e1 e2
[$ex| match $e1 with $list:clauses |] ->
prec precDot $
vcat (sep [ text "match",
nest 2 $ ppr0 e1,
text "with" ] : map alt clauses)
where
alt (N _ (CaClause xi ei)) =
hang (char '|' <+> ppr xi <+> text "->")
4
(ppr ei)
alt (N _ (CaAnti a)) = char '|' <+> ppr a
[$ex| let rec $list:bs in $e2 |] ->
prec precDot $
text "let" <+>
vcat (zipWith each ("rec" : repeat "and") bs) $$
text "in" <+> ppr e2
where
each kw (N _ (BnBind x t e)) =
-- This could be better by pulling some args out.
hang (hang (text kw <+> ppr x)
6
(colon <+> ppr t <+> equals))
2
(ppr e)
each kw (N _ (BnAnti a)) = text kw <+> ppr a
[$ex| let $decl:d in $e2 |] ->
prec precDot $
text "let" <+> ppr0 d $$
(text "in" >+> ppr e2)
[$ex| ($e1, $e2) |] ->
prec precCom $
sep [ ppr e1 <> comma, ppr1 e2 ]
[$ex| fun $_ : $_ -> $_ |] -> pprAbs e0
[$ex| $e1 $e2 |]
-> prec precApp $
sep [ ppr e1, ppr1 e2 ]
[$ex| fun '$_ -> $_ |] -> pprAbs e0
[$ex| $_ [$_] |] ->
prec precTApp $
cat [ ppr op,
brackets . fsep . punctuate comma $
map (pprPrec precCom) args ]
where
(args, op) = unfoldExTApp e0
[$ex| Pack[$opt:t1]($t2, $e) |] ->
prec precApp $
text "Pack" <> maybe empty (brackets . ppr0) t1 <+>
prec precCom (sep [ ppr1 t2 <> comma, ppr e ])
[$ex| ( $e : $t1 :> $t2 ) |] ->
prec precCast $
atPrec (precCast + 2) $
sep [ ppr e,
colon <+> ppr t1,
text ":>" <+> ppr t2 ]
[$ex| ( $e : $t1 ) |] ->
prec precCast $
atPrec (precCast + 2) $
sep [ ppr e,
colon <+> ppr t1 ]
[$ex| ( $e :> $t1 ) |] ->
prec precCast $
atPrec (precCast + 2) $
sep [ ppr e,
text ":>" <+> ppr t1 ]
[$ex| $anti:a |] -> ppr a
where
unfoldExpr [$ex| ($name:x $e1) $e2 |] = Just (e1, x, Just e2)
unfoldExpr [$ex| $name:x $e1 |] = Just (e1, x, Nothing)
unfoldExpr _ = Nothing
pprLet :: Doc -> Expr i -> Expr i -> Doc
pprLet pat e1 e2 = prec precDot $
hang (text "let" <+> pat <+> pprArgList args <+> equals
>+> ppr body <+> text "in")
(if isLet (view e2)
then 0
else 2)
(ppr e2)
where
(args, body) = unfoldExAbs e1
isLet (ExCase _ [_]) = True
isLet _ = False
pprAbs :: Expr i -> Doc
pprAbs e = prec precDot $
text "fun" <+> argsDoc <+> text "->"
>+> ppr body
where (args, body) = unfoldExAbs e
argsDoc = case args of
[Left ([$pa| _ |], [$ty|@! unit |])]
-> parens empty
[Left (x, t)] -> ppr x <+> char ':' <+> pprPrec (precArr + 1) t
_ -> pprArgList args
pprArgList :: [Either (Patt i, Type i) (TyVar i)] -> Doc
pprArgList = fsep . map eachArg . combine where
eachArg (Left ([$pa| _ |], [$ty|@! unit |]))
= parens empty
eachArg (Left (x, t)) = parens $
ppr0 x
>+> colon <+> ppr0 t
eachArg (Right tvs) = brackets .
sep .
punctuate comma $
map ppr tvs
--
combine :: [Either a b] -> [Either a [b]]
combine = foldr each [] where
each (Right b) (Right bs : es) = Right (b : bs) : es
each (Right b) es = Right [b] : es
each (Left a) es = Left a : es
instance Ppr (Patt i) where
ppr [$pa| _ |] = text "_"
ppr [$pa| $lid:l |] = ppr l
ppr [$pa| $quid:qu |] = ppr qu
ppr [$pa| $quid:qu $x |] = prec precApp $
ppr qu <+> ppr1 x
ppr [$pa| ($x, $y) |] = prec precCom $
ppr x <> comma <+> ppr1 y
ppr [$pa| $lit:lt |] = ppr lt
ppr [$pa| $x as $lid:l |] = prec precDot $
ppr1 x <+> text "as" <+> ppr l
ppr [$pa| Pack('$tv,$x) |] = prec precApp $
text "Pack" <+> pprPrec precCom (sep pair)
where pair = [ ppr1 tv <> comma, ppr x ]
ppr [$pa| $anti:a |] = ppr a
instance Ppr Lit where
ppr (LtInt i) = integer i
ppr (LtFloat f) = double f
ppr (LtStr s) = text (show s)
ppr (LtAnti a) = ppr a
--
-- Helper for pretty-printing type-like things -- doesn't require
-- underlying types, but does need to see the operator name.
--
data PprTyAppHelper i a
= PTAHBranch (QLid i) [a]
| PTAHLeaf a
instance Ppr a => Ppr (PprTyAppHelper i a) where
ppr (PTAHLeaf a) = ppr a
ppr _ = error "BUG! in PprTyAppHelper.ppr"
unfoldPTAH :: PprTyAppHelper i a ->
Maybe (PprTyAppHelper i a, String, Maybe (PprTyAppHelper i a))
unfoldPTAH (PTAHBranch (J [] l) [a, b])
= Just (PTAHLeaf a, unLid l, Just (PTAHLeaf b))
unfoldPTAH (PTAHBranch (J [] l) [a])
= Just (PTAHLeaf a, unLid l, Nothing)
unfoldPTAH _
= Nothing
pprTyApp :: Ppr a => QLid i -> [a] -> Doc
pprTyApp ql ts
| Just doc <- pprInfix unfoldPTAH (PTAHBranch ql ts)
= doc
pprTyApp ql [] = ppr ql
pprTyApp ql ts = prec precApp $ sep [ ppr ts, ppr ql ]
--
-- Instances
--
instance Show (Prog i) where showsPrec = showFromPpr
instance Show (Decl i) where showsPrec = showFromPpr
instance Show (TyDec i) where showsPrec = showFromPpr
instance Show (Expr i) where showsPrec = showFromPpr
instance Show (Patt i) where showsPrec = showFromPpr
instance Show Lit where showsPrec = showFromPpr
instance Show (Type i) where showsPrec = showFromPpr
instance Show (TyPat i) where showsPrec = showFromPpr
instance Show (QExp i) where showsPrec = showFromPpr
instance Show (SigItem i)where showsPrec = showFromPpr
instance Ppr Loc where pprPrec = pprFromShow
instance Ppr QLit where pprPrec = pprFromShow
instance Ppr Variance where pprPrec = pprFromShow
instance Ppr Quant where pprPrec = pprFromShow
instance Ppr (Lid i) where pprPrec = pprFromShow
instance Ppr (Uid i) where pprPrec = pprFromShow
instance Ppr (BIdent i)where pprPrec = pprFromShow
instance Ppr (TyVar i) where pprPrec = pprFromShow
instance Ppr Anti where pprPrec = pprFromShow
instance (Show p, Show k) => Ppr (Path p k) where pprPrec = pprFromShow