CPython.Simple.Instances

Documentation

class ToPy a where

ToPy instances indicate that a type can be marshalled from Haskell to Python automatically

For example, ToPy Integer indicates that we know how to take a Haskell Integer and convert it into a Python int object

Methods

toPy :: a -> IO SomeObject

Takes some Haskell type, and converts it to a Python object by going over FFI

Generally you'll only need to call toPy manually on some type when writing your own ToPy instances for another type

Instances

ToPy Text

Defined in CPython.Simple.Instances

Methods

toPy :: Text -> IO SomeObject

ToPy String

Defined in CPython.Simple.Instances

Methods

toPy :: String -> IO SomeObject

ToPy Integer

Defined in CPython.Simple.Instances

Methods

toPy :: Integer -> IO SomeObject

ToPy Bool

Defined in CPython.Simple.Instances

Methods

toPy :: Bool -> IO SomeObject

ToPy Char

Defined in CPython.Simple.Instances

Methods

toPy :: Char -> IO SomeObject

ToPy Double

Defined in CPython.Simple.Instances

Methods

toPy :: Double -> IO SomeObject

ToPy a => ToPy (Maybe a)

Defined in CPython.Simple.Instances

Methods

toPy :: Maybe a -> IO SomeObject

ToPy a => ToPy [a]

Defined in CPython.Simple.Instances

Methods

toPy :: [a] -> IO SomeObject

(ToPy a, ToPy b) => ToPy (a, b)

Defined in CPython.Simple.Instances

Methods

toPy :: (a, b) -> IO SomeObject

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

Defined in CPython.Simple.Instances

Methods

toPy :: (a, b, c) -> IO SomeObject

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

Defined in CPython.Simple.Instances

Methods

toPy :: (a, b, c, d) -> IO SomeObject

class FromPy a where

FromPy instances indicate that a type can be marshalled from Python to Haskell automatically

For example, FromPy Integer indicates that we know how to take some Python object and convert it into a Haskell Integer. If the Python object is int, then we can cast properly. Failed casts throw a PyCastException

Methods

fromPy :: SomeObject -> IO a

Takes some Python object, and converts it to the corresponding Haskell type by going over FFI. Might throw a PyCastException

Generally you'll only need to call fromPy manually on some type when writing your own FromPy instances for another type

Instances

FromPy Text

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO Text

FromPy String

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO String

FromPy Integer

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO Integer

FromPy ()

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO ()

FromPy Bool

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO Bool

FromPy Char

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO Char

FromPy Double

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO Double

FromPy a => FromPy (Maybe a)

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO (Maybe a)

FromPy a => FromPy [a]

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO [a]

(FromPy a, FromPy b) => FromPy (a, b)

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO (a, b)

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

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO (a, b, c)

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

Defined in CPython.Simple.Instances

Methods

fromPy :: SomeObject -> IO (a, b, c, d)

data PyCastException

An exception representing a failed cast from a Python object to Haskell value, usually because the expected type of the Python object was not correct.

Carries a String which represents the name of the expected Haskell type which caused a failed cast. If using easyFromPy, this String is found with typeRep

Constructors

PyCastException String

Instances

Exception PyCastException

Defined in CPython.Simple.Instances

Methods

toException :: PyCastException -> SomeException

fromException :: SomeException -> Maybe PyCastException

displayException :: PyCastException -> String

Show PyCastException

Defined in CPython.Simple.Instances

Methods

showsPrec :: Int -> PyCastException -> ShowS

show :: PyCastException -> String

showList :: [PyCastException] -> ShowS

easyToPy

Arguments

:: Object p

=> (h -> IO p)

python to- conversion, e.g. Py.toFloat

-> h

haskell type being converted

-> IO SomeObject

Python object

Helper that lets you convert a Haskell value to a Python object by providing both a Python conversion function (from the Haskell type, over FFI, to some Python Object) as well as the Haskell value

Lets you define toPy with just a Python conversion function

easyFromPy

Arguments

:: (Concrete p, Typeable h)

=> (p -> IO h)

python from- conversion, e.g. Py.fromFloat

-> Proxy h

proxy for the type being converted to

-> SomeObject

python object to cast from

-> IO h

Haskell value

Helper that takes a conversion function and a Python object, and casts the Python object into a Haskell value.

Lets you define fromPy with just a Python conversion function

We use Proxy to infer the type name for use in case of a failed cast. In the context of defining an instance, this type will be inferrable, so you can just provide a Proxy value