Safe Haskell	None
Language	GHC2021

GHC.Runtime.Heap.Inspect

Contents

Entry points and types
Utils

Synopsis

cvObtainTerm :: HscEnv -> Int -> Bool -> RttiType -> ForeignHValue -> IO Term
cvReconstructType :: HscEnv -> Int -> GhciType -> ForeignHValue -> IO (Maybe Type)
improveRTTIType :: HscEnv -> RttiType -> RttiType -> Maybe Subst
data Term
- = Term {
  - ty :: RttiType
  - dc :: Either String DataCon
  - val :: ForeignHValue
  - subTerms :: [Term]
  }
- | Prim {
  - ty :: RttiType
  - valRaw :: [Word]
  }
- | Suspension {
  - ctype :: ClosureType
  - ty :: RttiType
  - val :: ForeignHValue
  - bound_to :: Maybe Name
  }
- | NewtypeWrap {
  - ty :: RttiType
  - dc :: Either String DataCon
  - wrapped_term :: Term
  }
- | RefWrap {
  - ty :: RttiType
  - wrapped_term :: Term
  }
isFullyEvaluatedTerm :: Term -> Bool
termType :: Term -> RttiType
mapTermType :: (RttiType -> Type) -> Term -> Term
termTyCoVars :: Term -> TyCoVarSet
foldTerm :: TermFold a -> Term -> a
data TermFold a = TermFold {
- fTerm :: TermProcessor a a
- fPrim :: RttiType -> [Word] -> a
- fSuspension :: ClosureType -> RttiType -> ForeignHValue -> Maybe Name -> a
- fNewtypeWrap :: RttiType -> Either String DataCon -> a -> a
- fRefWrap :: RttiType -> a -> a
}
cPprTerm :: Monad m => CustomTermPrinter m -> Term -> m SDoc
cPprTermBase :: Monad m => CustomTermPrinter m
constrClosToName :: HscEnv -> GenClosure a -> IO (Either String Name)

Entry points and types

cvObtainTerm Source #

Arguments

:: HscEnv
-> Int	How many times to recurse for subterms
-> Bool	Force thunks
-> RttiType	Type of the object to reconstruct
-> ForeignHValue	Object to reconstruct
-> IO Term

Term reconstruction

Given a pointer to a heap object (HValue) and its type, build a Term representation of the object. Subterms (objects in the payload) are also built up to the given max_depth. After max_depth any subterms will appear as Suspensions. Any thunks found while traversing the object will be forced based on force parameter.

Types of terms will be refined based on constructors we find during term reconstruction. See cvReconstructType for an overview of how type reconstruction works.

cvReconstructType Source #

Arguments

:: HscEnv
-> Int	How many times to recurse for subterms
-> GhciType	Type to refine
-> ForeignHValue	Refine the type using this value
-> IO (Maybe Type)

Fast, breadth-first Type reconstruction

Given a heap object (HValue) and its (possibly polymorphic) type (usually obtained in GHCi), try to reconstruct a more monomorphic type of the object. This is used for improving type information in debugger. For example, if we have a polymorphic function:

sumNumList :: Num a => [a] -> a sumNumList [] = 0 sumNumList (x : xs) = x + sumList xs

and add a breakpoint to it:

ghci> break sumNumList ghci> sumNumList ([0 .. 9] :: [Int])

ghci shows us more precise types than just as:

Stopped in Main.sumNumList, debugger.hs:3:23-39 _result :: Int = _ x :: Int = 0 xs :: [Int] = _

improveRTTIType :: HscEnv -> RttiType -> RttiType -> Maybe Subst Source #

data Term Source #

Constructors

Term
Fields ty :: RttiType dc :: Either String DataCon val :: ForeignHValue subTerms :: [Term]
Prim
Fields ty :: RttiType valRaw :: [Word]
Suspension
Fields ctype :: ClosureType ty :: RttiType val :: ForeignHValue bound_to :: Maybe Name
NewtypeWrap
Fields ty :: RttiType dc :: Either String DataCon wrapped_term :: Term
RefWrap
Fields ty :: RttiType wrapped_term :: Term

Instances

Instances details

Outputable Term Source #
Instance details Defined in GHC.Runtime.Heap.Inspect Methods ppr :: Term -> SDoc Source #

Utils

isFullyEvaluatedTerm :: Term -> Bool Source #

termType :: Term -> RttiType Source #

mapTermType :: (RttiType -> Type) -> Term -> Term Source #

termTyCoVars :: Term -> TyCoVarSet Source #

foldTerm :: TermFold a -> Term -> a Source #

data TermFold a Source #

Constructors

TermFold
Fields fTerm :: TermProcessor a a fPrim :: RttiType -> [Word] -> a fSuspension :: ClosureType -> RttiType -> ForeignHValue -> Maybe Name -> a fNewtypeWrap :: RttiType -> Either String DataCon -> a -> a fRefWrap :: RttiType -> a -> a

cPprTerm :: Monad m => CustomTermPrinter m -> Term -> m SDoc Source #

Takes a list of custom printers with a explicit recursion knot and a term, and returns the output of the first successful printer, or the default printer

cPprTermBase :: Monad m => CustomTermPrinter m Source #

constrClosToName :: HscEnv -> GenClosure a -> IO (Either String Name) Source #