-- | Provides facilities for pretty-printing 'Nabla's in a way appropriate for
-- user facing pattern match warnings.
module GHC.HsToCore.Pmc.Ppr (
      pprUncovered
    ) where

import GHC.Prelude

import GHC.Data.List.Infinite (Infinite (..))
import qualified GHC.Data.List.Infinite as Inf
import GHC.Types.Basic
import GHC.Types.Id
import GHC.Types.Var.Env
import GHC.Types.Unique.DFM
import GHC.Core.ConLike
import GHC.Core.DataCon
import GHC.Builtin.Types
import GHC.Utils.Outputable
import GHC.Utils.Panic
import Control.Monad.Trans.RWS.CPS
import GHC.Data.Maybe
import Data.List.NonEmpty (NonEmpty, nonEmpty, toList)

import GHC.HsToCore.Pmc.Types

-- | Pretty-print the guts of an uncovered value vector abstraction, i.e., its
-- components and refutable shapes associated to any mentioned variables.
--
-- Example for @([Just p, q], [p :-> [3,4], q :-> [0,5]])@:
--
-- @
-- (Just p) q
--     where p is not one of {3, 4}
--           q is not one of {0, 5}
-- @
--
-- When the set of refutable shapes contains more than 3 elements, the
-- additional elements are indicated by "...".
pprUncovered :: Nabla -> [Id] -> SDoc
pprUncovered :: Nabla -> [Id] -> SDoc
pprUncovered Nabla
nabla [Id]
vas
  | UniqDFM Id (SDoc, [PmAltCon]) -> Bool
forall {k} (key :: k) elt. UniqDFM key elt -> Bool
isNullUDFM UniqDFM Id (SDoc, [PmAltCon])
refuts = [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
fsep [SDoc]
vec -- there are no refutations
  | Bool
otherwise         = SDoc -> Int -> SDoc -> SDoc
hang ([SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
fsep [SDoc]
vec) Int
4 (SDoc -> SDoc) -> SDoc -> SDoc
forall a b. (a -> b) -> a -> b
$
                          String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"where" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> [SDoc] -> SDoc
forall doc. IsDoc doc => [doc] -> doc
vcat (((Unique, (SDoc, [PmAltCon])) -> SDoc)
-> [(Unique, (SDoc, [PmAltCon]))] -> [SDoc]
forall a b. (a -> b) -> [a] -> [b]
map ((SDoc, [PmAltCon]) -> SDoc
pprRefutableShapes ((SDoc, [PmAltCon]) -> SDoc)
-> ((Unique, (SDoc, [PmAltCon])) -> (SDoc, [PmAltCon]))
-> (Unique, (SDoc, [PmAltCon]))
-> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Unique, (SDoc, [PmAltCon])) -> (SDoc, [PmAltCon])
forall a b. (a, b) -> b
snd) (UniqDFM Id (SDoc, [PmAltCon]) -> [(Unique, (SDoc, [PmAltCon]))]
forall {k} (key :: k) elt. UniqDFM key elt -> [(Unique, elt)]
udfmToList UniqDFM Id (SDoc, [PmAltCon])
refuts))
  where
    init_prec :: PprPrec
init_prec
      -- No outer parentheses when it's a unary pattern by assuming lowest
      -- precedence
      | [Id
_] <- [Id]
vas   = PprPrec
topPrec
      | Bool
otherwise    = PprPrec
appPrec
    ppr_action :: RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
ppr_action       = (Id
 -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc)
-> [Id]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (PprPrec
-> Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmVar PprPrec
init_prec) [Id]
vas
    ([SDoc]
vec, DIdEnv (Id, SDoc)
renamings) = Nabla
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
-> ([SDoc], DIdEnv (Id, SDoc))
forall a. Nabla -> PmPprM a -> (a, DIdEnv (Id, SDoc))
runPmPpr Nabla
nabla RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
ppr_action
    refuts :: UniqDFM Id (SDoc, [PmAltCon])
refuts           = Nabla -> DIdEnv (Id, SDoc) -> UniqDFM Id (SDoc, [PmAltCon])
prettifyRefuts Nabla
nabla DIdEnv (Id, SDoc)
renamings

-- | Output refutable shapes of a variable in the form of @var is not one of {2,
-- Nothing, 3}@. Will never print more than 3 refutable shapes, the tail is
-- indicated by an ellipsis.
pprRefutableShapes :: (SDoc,[PmAltCon]) -> SDoc
pprRefutableShapes :: (SDoc, [PmAltCon]) -> SDoc
pprRefutableShapes (SDoc
var, [PmAltCon]
alts)
  = SDoc
var SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"is not one of" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> [PmAltCon] -> SDoc
format_alts [PmAltCon]
alts
  where
    format_alts :: [PmAltCon] -> SDoc
format_alts = SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
braces (SDoc -> SDoc) -> ([PmAltCon] -> SDoc) -> [PmAltCon] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
fsep ([SDoc] -> SDoc) -> ([PmAltCon] -> [SDoc]) -> [PmAltCon] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate SDoc
forall doc. IsLine doc => doc
comma ([SDoc] -> [SDoc])
-> ([PmAltCon] -> [SDoc]) -> [PmAltCon] -> [SDoc]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [SDoc] -> [SDoc]
forall {a}. IsLine a => [a] -> [a]
shorten ([SDoc] -> [SDoc])
-> ([PmAltCon] -> [SDoc]) -> [PmAltCon] -> [SDoc]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (PmAltCon -> SDoc) -> [PmAltCon] -> [SDoc]
forall a b. (a -> b) -> [a] -> [b]
map PmAltCon -> SDoc
ppr_alt
    shorten :: [a] -> [a]
shorten (a
a:a
b:a
c:a
_:[a]
_)       = a
aa -> [a] -> [a]
forall a. a -> [a] -> [a]
:a
ba -> [a] -> [a]
forall a. a -> [a] -> [a]
:a
ca -> [a] -> [a]
forall a. a -> [a] -> [a]
:[String -> a
forall doc. IsLine doc => String -> doc
text String
"..."]
    shorten [a]
xs                = [a]
xs
    ppr_alt :: PmAltCon -> SDoc
ppr_alt (PmAltConLike ConLike
cl) = ConLike -> SDoc
forall a. Outputable a => a -> SDoc
ppr ConLike
cl
    ppr_alt (PmAltLit PmLit
lit)    = PmLit -> SDoc
forall a. Outputable a => a -> SDoc
ppr PmLit
lit

{- 1. Literals
~~~~~~~~~~~~~~
Starting with a function definition like:

    f :: Int -> Bool
    f 5 = True
    f 6 = True

The uncovered set looks like:
    { var |> var /= 5, var /= 6 }

Yet, we would like to print this nicely as follows:
   x , where x not one of {5,6}

Since these variables will be shown to the programmer, we give them better names
(t1, t2, ..) in 'prettifyRefuts', hence the SDoc in 'PrettyPmRefutEnv'.

2. Residual Constraints
~~~~~~~~~~~~~~~~~~~~~~~
Unhandled constraints that refer to HsExpr are typically ignored by the solver
(it does not even substitute in HsExpr so they are even printed as wildcards).
Additionally, the oracle returns a substitution if it succeeds so we apply this
substitution to the vectors before printing them out (see function `pprOne' in
"GHC.HsToCore.Pmc") to be more precise.
-}

-- | Extract and assigns pretty names to constraint variables with refutable
-- shapes.
prettifyRefuts :: Nabla -> DIdEnv (Id, SDoc) -> DIdEnv (SDoc, [PmAltCon])
prettifyRefuts :: Nabla -> DIdEnv (Id, SDoc) -> UniqDFM Id (SDoc, [PmAltCon])
prettifyRefuts Nabla
nabla = [(Unique, (SDoc, [PmAltCon]))] -> UniqDFM Id (SDoc, [PmAltCon])
forall {k} elt (key :: k). [(Unique, elt)] -> UniqDFM key elt
listToUDFM_Directly ([(Unique, (SDoc, [PmAltCon]))] -> UniqDFM Id (SDoc, [PmAltCon]))
-> (DIdEnv (Id, SDoc) -> [(Unique, (SDoc, [PmAltCon]))])
-> DIdEnv (Id, SDoc)
-> UniqDFM Id (SDoc, [PmAltCon])
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ((Unique, (Id, SDoc)) -> (Unique, (SDoc, [PmAltCon])))
-> [(Unique, (Id, SDoc))] -> [(Unique, (SDoc, [PmAltCon]))]
forall a b. (a -> b) -> [a] -> [b]
map (Unique, (Id, SDoc)) -> (Unique, (SDoc, [PmAltCon]))
attach_refuts ([(Unique, (Id, SDoc))] -> [(Unique, (SDoc, [PmAltCon]))])
-> (DIdEnv (Id, SDoc) -> [(Unique, (Id, SDoc))])
-> DIdEnv (Id, SDoc)
-> [(Unique, (SDoc, [PmAltCon]))]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. DIdEnv (Id, SDoc) -> [(Unique, (Id, SDoc))]
forall {k} (key :: k) elt. UniqDFM key elt -> [(Unique, elt)]
udfmToList
  where
    attach_refuts :: (Unique, (Id, SDoc)) -> (Unique, (SDoc, [PmAltCon]))
attach_refuts (Unique
u, (Id
x, SDoc
sdoc)) = (Unique
u, (SDoc
sdoc, Nabla -> Id -> [PmAltCon]
lookupRefuts Nabla
nabla Id
x))


type PmPprM a = RWS Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) a

-- Try nice names p,q,r,s,t before using the (ugly) t_i
nameList :: Infinite SDoc
nameList :: Infinite SDoc
nameList = (String -> SDoc) -> [String] -> [SDoc]
forall a b. (a -> b) -> [a] -> [b]
map String -> SDoc
forall doc. IsLine doc => String -> doc
text [String
"p",String
"q",String
"r",String
"s",String
"t"] [SDoc] -> Infinite SDoc -> Infinite SDoc
forall (f :: * -> *) a.
Foldable f =>
f a -> Infinite a -> Infinite a
Inf.++ ((Int -> (SDoc, Int)) -> Int -> Infinite SDoc)
-> Int -> (Int -> (SDoc, Int)) -> Infinite SDoc
forall a b c. (a -> b -> c) -> b -> a -> c
flip (Int -> (SDoc, Int)) -> Int -> Infinite SDoc
forall b a. (b -> (a, b)) -> b -> Infinite a
Inf.unfoldr (Int
0 :: Int) (\ Int
u -> (String -> SDoc
forall doc. IsLine doc => String -> doc
text (Char
't'Char -> String -> String
forall a. a -> [a] -> [a]
:Int -> String
forall a. Show a => a -> String
show Int
u), Int
uInt -> Int -> Int
forall a. Num a => a -> a -> a
+Int
1))

runPmPpr :: Nabla -> PmPprM a -> (a, DIdEnv (Id, SDoc))
runPmPpr :: forall a. Nabla -> PmPprM a -> (a, DIdEnv (Id, SDoc))
runPmPpr Nabla
nabla PmPprM a
m = case PmPprM a
-> Nabla
-> (DIdEnv (Id, SDoc), Infinite SDoc)
-> (a, (DIdEnv (Id, SDoc), Infinite SDoc), ())
forall w r s a. Monoid w => RWS r w s a -> r -> s -> (a, s, w)
runRWS PmPprM a
m Nabla
nabla (DIdEnv (Id, SDoc)
forall a. DVarEnv a
emptyDVarEnv, Infinite SDoc
nameList) of
  (a
a, (DIdEnv (Id, SDoc)
renamings, Infinite SDoc
_), ()
_) -> (a
a, DIdEnv (Id, SDoc)
renamings)

-- | Allocates a new, clean name for the given 'Id' if it doesn't already have
-- one.
getCleanName :: Id -> PmPprM SDoc
getCleanName :: Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
getCleanName Id
x = do
  (renamings, name_supply) <- RWST
  Nabla
  ()
  (DIdEnv (Id, SDoc), Infinite SDoc)
  Identity
  (DIdEnv (Id, SDoc), Infinite SDoc)
forall (m :: * -> *) r w s. Monad m => RWST r w s m s
get
  let Inf clean_name name_supply' = name_supply
  case lookupDVarEnv renamings x of
    Just (Id
_, SDoc
nm) -> SDoc
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall a.
a -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity a
forall (f :: * -> *) a. Applicative f => a -> f a
pure SDoc
nm
    Maybe (Id, SDoc)
Nothing -> do
      (DIdEnv (Id, SDoc), Infinite SDoc)
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity ()
forall (m :: * -> *) s r w. Monad m => s -> RWST r w s m ()
put (DIdEnv (Id, SDoc) -> Id -> (Id, SDoc) -> DIdEnv (Id, SDoc)
forall a. DVarEnv a -> Id -> a -> DVarEnv a
extendDVarEnv DIdEnv (Id, SDoc)
renamings Id
x (Id
x, SDoc
clean_name), Infinite SDoc
name_supply')
      SDoc
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall a.
a -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity a
forall (f :: * -> *) a. Applicative f => a -> f a
pure SDoc
clean_name

checkRefuts :: Id -> PmPprM (Maybe SDoc) -- the clean name if it has negative info attached
checkRefuts :: Id -> PmPprM (Maybe SDoc)
checkRefuts Id
x = do
  nabla <- RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity Nabla
forall (m :: * -> *) r w s. Monad m => RWST r w s m r
ask
  case lookupRefuts nabla x of
    [] -> Maybe SDoc -> PmPprM (Maybe SDoc)
forall a.
a -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity a
forall (f :: * -> *) a. Applicative f => a -> f a
pure Maybe SDoc
forall a. Maybe a
Nothing -- Will just be a wildcard later on
    [PmAltCon]
_  -> SDoc -> Maybe SDoc
forall a. a -> Maybe a
Just (SDoc -> Maybe SDoc)
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
-> PmPprM (Maybe SDoc)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
getCleanName Id
x

-- | Pretty print a variable, but remember to prettify the names of the variables
-- that refer to neg-literals. The ones that cannot be shown are printed as
-- underscores.
pprPmVar :: PprPrec -> Id -> PmPprM SDoc
pprPmVar :: PprPrec
-> Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmVar PprPrec
prec Id
x = do
  nabla <- RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity Nabla
forall (m :: * -> *) r w s. Monad m => RWST r w s m r
ask
  case lookupSolution nabla x of
    Just (PACA PmAltCon
alt [Id]
_tvs [Id]
args) -> PprPrec
-> PmAltCon
-> [Id]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmAltCon PprPrec
prec PmAltCon
alt [Id]
args
    Maybe PmAltConApp
Nothing                   -> SDoc -> Maybe SDoc -> SDoc
forall a. a -> Maybe a -> a
fromMaybe SDoc
forall doc. IsLine doc => doc
underscore (Maybe SDoc -> SDoc)
-> PmPprM (Maybe SDoc)
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Id -> PmPprM (Maybe SDoc)
checkRefuts Id
x

pprPmAltCon :: PprPrec -> PmAltCon -> [Id] -> PmPprM SDoc
pprPmAltCon :: PprPrec
-> PmAltCon
-> [Id]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmAltCon PprPrec
_prec (PmAltLit PmLit
l)      [Id]
_    = SDoc
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall a.
a -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity a
forall (f :: * -> *) a. Applicative f => a -> f a
pure (PmLit -> SDoc
forall a. Outputable a => a -> SDoc
ppr PmLit
l)
pprPmAltCon PprPrec
prec  (PmAltConLike ConLike
cl) [Id]
args = do
  nabla <- RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity Nabla
forall (m :: * -> *) r w s. Monad m => RWST r w s m r
ask
  pprConLike nabla prec cl args

pprConLike :: Nabla -> PprPrec -> ConLike -> [Id] -> PmPprM SDoc
pprConLike :: Nabla
-> PprPrec
-> ConLike
-> [Id]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprConLike Nabla
nabla PprPrec
_prec ConLike
cl [Id]
args
  | Just PmExprList
pm_expr_list <- Nabla -> PmAltCon -> [Id] -> Maybe PmExprList
pmExprAsList Nabla
nabla (ConLike -> PmAltCon
PmAltConLike ConLike
cl) [Id]
args
  = case PmExprList
pm_expr_list of
      NilTerminated [Id]
list ->
        SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
brackets (SDoc -> SDoc) -> ([SDoc] -> SDoc) -> [SDoc] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
fsep ([SDoc] -> SDoc) -> ([SDoc] -> [SDoc]) -> [SDoc] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate SDoc
forall doc. IsLine doc => doc
comma ([SDoc] -> SDoc)
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (Id
 -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc)
-> [Id]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (PprPrec
-> Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmVar PprPrec
appPrec) [Id]
list
      WcVarTerminated NonEmpty Id
pref Id
x ->
        SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens   (SDoc -> SDoc) -> ([SDoc] -> SDoc) -> [SDoc] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [SDoc] -> SDoc
fcat ([SDoc] -> SDoc) -> ([SDoc] -> [SDoc]) -> [SDoc] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate SDoc
forall doc. IsLine doc => doc
colon ([SDoc] -> SDoc)
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (Id
 -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc)
-> [Id]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (PprPrec
-> Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmVar PprPrec
appPrec) (NonEmpty Id -> [Id]
forall a. NonEmpty a -> [a]
toList NonEmpty Id
pref [Id] -> [Id] -> [Id]
forall a. [a] -> [a] -> [a]
++ [Id
x])
pprConLike Nabla
_nabla PprPrec
_prec (RealDataCon DataCon
con) [Id]
args
  | DataCon -> Bool
isUnboxedTupleDataCon DataCon
con
  , let hash_parens :: doc -> doc
hash_parens doc
doc = String -> doc
forall doc. IsLine doc => String -> doc
text String
"(#" doc -> doc -> doc
forall doc. IsLine doc => doc -> doc -> doc
<+> doc
doc doc -> doc -> doc
forall doc. IsLine doc => doc -> doc -> doc
<+> String -> doc
forall doc. IsLine doc => String -> doc
text String
"#)"
  = SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
hash_parens (SDoc -> SDoc) -> ([SDoc] -> SDoc) -> [SDoc] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
fsep ([SDoc] -> SDoc) -> ([SDoc] -> [SDoc]) -> [SDoc] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate SDoc
forall doc. IsLine doc => doc
comma ([SDoc] -> SDoc)
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (Id
 -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc)
-> [Id]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (PprPrec
-> Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmVar PprPrec
appPrec) [Id]
args
  | DataCon -> Bool
isTupleDataCon DataCon
con
  = SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens (SDoc -> SDoc) -> ([SDoc] -> SDoc) -> [SDoc] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [SDoc] -> SDoc
forall doc. IsLine doc => [doc] -> doc
fsep ([SDoc] -> SDoc) -> ([SDoc] -> [SDoc]) -> [SDoc] -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. SDoc -> [SDoc] -> [SDoc]
forall doc. IsLine doc => doc -> [doc] -> [doc]
punctuate SDoc
forall doc. IsLine doc => doc
comma ([SDoc] -> SDoc)
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (Id
 -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc)
-> [Id]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (PprPrec
-> Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmVar PprPrec
appPrec) [Id]
args
pprConLike Nabla
_nabla PprPrec
prec ConLike
cl [Id]
args
  | ConLike -> Bool
conLikeIsInfix ConLike
cl = case [Id]
args of
      [Id
x, Id
y] -> do x' <- PprPrec
-> Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmVar PprPrec
funPrec Id
x
                   y' <- pprPmVar funPrec y
                   return (cparen (prec > opPrec) (x' <+> ppr cl <+> y'))
      -- can it be infix but have more than two arguments?
      [Id]
list   -> String
-> SDoc
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"pprConLike:" ([Id] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Id]
list)
  | [Id] -> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [Id]
args = SDoc
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
forall a.
a -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity a
forall (m :: * -> *) a. Monad m => a -> m a
return (ConLike -> SDoc
forall a. Outputable a => a -> SDoc
ppr ConLike
cl)
  | Bool
otherwise = do args' <- (Id
 -> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc)
-> [Id]
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity [SDoc]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (PprPrec
-> Id
-> RWST Nabla () (DIdEnv (Id, SDoc), Infinite SDoc) Identity SDoc
pprPmVar PprPrec
appPrec) [Id]
args
                   return (cparen (prec > funPrec) (fsep (ppr cl : args')))

-- | The result of 'pmExprAsList'.
data PmExprList
  = NilTerminated [Id]
  | WcVarTerminated (NonEmpty Id) Id

-- | Extract a list of 'Id's out of a sequence of cons cells, optionally
-- terminated by a wildcard variable instead of @[]@. Some examples:
--
-- * @pmExprAsList (1:2:[]) == Just ('NilTerminated' [1,2])@, a regular,
--   @[]@-terminated list. Should be pretty-printed as @[1,2]@.
-- * @pmExprAsList (1:2:x) == Just ('WcVarTerminated' [1,2] x)@, a list prefix
--   ending in a wildcard variable x (of list type). Should be pretty-printed as
--   (1:2:_).
-- * @pmExprAsList [] == Just ('NilTerminated' [])@
pmExprAsList :: Nabla -> PmAltCon -> [Id] -> Maybe PmExprList
pmExprAsList :: Nabla -> PmAltCon -> [Id] -> Maybe PmExprList
pmExprAsList Nabla
nabla = [Id] -> PmAltCon -> [Id] -> Maybe PmExprList
go_con []
  where
    go_var :: [Id] -> Id -> Maybe PmExprList
go_var [Id]
rev_pref Id
x
      | Just (PACA PmAltCon
alt [Id]
_tvs [Id]
args) <- Nabla -> Id -> Maybe PmAltConApp
lookupSolution Nabla
nabla Id
x
      = [Id] -> PmAltCon -> [Id] -> Maybe PmExprList
go_con [Id]
rev_pref PmAltCon
alt [Id]
args
    go_var [Id]
rev_pref Id
x
      | Just NonEmpty Id
pref <- [Id] -> Maybe (NonEmpty Id)
forall a. [a] -> Maybe (NonEmpty a)
nonEmpty ([Id] -> [Id]
forall a. [a] -> [a]
reverse [Id]
rev_pref)
      = PmExprList -> Maybe PmExprList
forall a. a -> Maybe a
Just (NonEmpty Id -> Id -> PmExprList
WcVarTerminated NonEmpty Id
pref Id
x)
    go_var [Id]
_ Id
_
      = Maybe PmExprList
forall a. Maybe a
Nothing

    go_con :: [Id] -> PmAltCon -> [Id] -> Maybe PmExprList
go_con [Id]
rev_pref (PmAltConLike (RealDataCon DataCon
c)) [Id]
es
      | DataCon
c DataCon -> DataCon -> Bool
forall a. Eq a => a -> a -> Bool
== DataCon
nilDataCon
      = Bool -> Maybe PmExprList -> Maybe PmExprList
forall a. HasCallStack => Bool -> a -> a
assert ([Id] -> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [Id]
es) (Maybe PmExprList -> Maybe PmExprList)
-> Maybe PmExprList -> Maybe PmExprList
forall a b. (a -> b) -> a -> b
$ PmExprList -> Maybe PmExprList
forall a. a -> Maybe a
Just ([Id] -> PmExprList
NilTerminated ([Id] -> [Id]
forall a. [a] -> [a]
reverse [Id]
rev_pref))
      | DataCon
c DataCon -> DataCon -> Bool
forall a. Eq a => a -> a -> Bool
== DataCon
consDataCon
      = Bool -> Maybe PmExprList -> Maybe PmExprList
forall a. HasCallStack => Bool -> a -> a
assert ([Id] -> Int
forall a. [a] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length [Id]
es Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
2) (Maybe PmExprList -> Maybe PmExprList)
-> Maybe PmExprList -> Maybe PmExprList
forall a b. (a -> b) -> a -> b
$ [Id] -> Id -> Maybe PmExprList
go_var ([Id]
es [Id] -> Int -> Id
forall a. HasCallStack => [a] -> Int -> a
!! Int
0 Id -> [Id] -> [Id]
forall a. a -> [a] -> [a]
: [Id]
rev_pref) ([Id]
es [Id] -> Int -> Id
forall a. HasCallStack => [a] -> Int -> a
!! Int
1)
    go_con [Id]
_ PmAltCon
_ [Id]
_
      = Maybe PmExprList
forall a. Maybe a
Nothing