Stg.Marshal.FromStg

Extract Haskell values from running STG programs.

Documentation

class FromStg value where

Look up the value of a global variable.

Instances of this class should have a corresponding ToStg instance to inject a value into the program, with the two being inverse to each other (up to forcing the generated thunks).

Minimal complete definition

fromStgAddr

Methods

fromStg

Arguments

:: StgState

-> Var

Name of the global, e.g. main

-> Either FromStgError value

Retrieve the value of a global variable.

fromStgAddr :: StgState -> MemAddr -> Either FromStgError value

Retrieve the value of a heap address.

fromStgPrim :: Integer -> Either FromStgError value

Used only for looking up primitive integers.

Instances

FromStg Bool

FromStg Integer

Boxed (Int# 1#) or unboxed (1#)

FromStg ()

FromStg a => FromStg [a]

FromStg a => FromStg (Maybe a)

(FromStg a, FromStg b) => FromStg (Either a b)

(FromStg a, FromStg b) => FromStg (a, b)

(FromStg a, FromStg b, FromStg c) => FromStg (a, b, c)

(FromStg a, FromStg b, FromStg c, FromStg d) => FromStg (a, b, c, d)

(FromStg a, FromStg b, FromStg c, FromStg d, FromStg e) => FromStg (a, b, c, d, e)

data FromStgError

Constructors

TypeMismatch

e.g. asking for an Int# at an address that contains a Cons

IsWrongLambdaType LambdaType

Tried retrieving a non-constructor

IsBlackhole

Tried retrieving a black hole

BadArity

e.g. Cons x y z

NotFound NotInScope

An unsuccessful variable lookup

AddrNotOnHeap

NoConstructorMatch

None of the given alternatives matched the given constructor, e.g. when trying to receive a Left as a Just

Instances

Eq FromStgError

Ord FromStgError

Show FromStgError