Effectful.Internal.Env

The enviroment for Eff.

This module is intended for internal use only, and may change without warning in subsequent releases.

Documentation

data Env (es :: [Effect])

A mutable, extensible record indexed by effect data types.

Safe operations

emptyEnv :: IO (Env '[])

Create an empty environment.

cloneEnv :: Env es -> IO (Env es)

Clone the environment.

sizeEnv :: Env es -> IO Int

Get the current size of the environment.

takeLastEnv :: HasCallStack => Int -> Env es0 -> IO (Env es)

Take last k values from the top of the environment.

getEnv :: forall e es. (HasCallStack, e :> es) => Env es -> IO e

Extract a specific data type from the environment.

checkSizeEnv :: HasCallStack => Int -> Env es -> IO ()

Check that the size of the environment is the same as the expected value.

Extending and shrinking

unsafeReplaceEnv :: HasCallStack => Env es -> Env es -> IO ()

Replace the first argument with the second one in place.

unsafeConsEnv :: HasCallStack => e -> Env es -> IO (Env (e ': es))

Extend the environment with a new data type in place.

unsafeAppendEnv :: HasCallStack => Env es0 -> Env es1 -> IO (Env es)

Extend the first environment with the second one in place.

unsafeTrimEnv :: HasCallStack => Int -> Env es -> IO (Env es0)

Trim the environment to the given size in place.

Data retrieval and update

unsafePutEnv :: forall e es. (HasCallStack, e :> es) => e -> Env es -> IO ()

Replace the data type in the environment with a new value in place.

unsafeModifyEnv :: forall e es. (HasCallStack, e :> es) => (e -> e) -> Env es -> IO ()

Modify the data type in the environment in place.

unsafeStateEnv :: forall e es a. (HasCallStack, e :> es) => (e -> (a, e)) -> Env es -> IO a

Modify the data type in the enviroment in place and return a value.