Safe Haskell	None
Language	GHC2021

KDL.Decoder.Internal.DecodeM

Contents

Decoding errors
DecodeM monad

Synopsis

module KDL.Decoder.Internal.Error
data DecodeM a
- = DecodeM_Found a DecodeHints
- | DecodeM_Fail (NonEmpty BaseDecodeError)
type DecodeHints = [BaseDecodeError]
runDecodeM :: DecodeM a -> Either DecodeError a
decodeThrow :: DecodeErrorKind -> DecodeM a
failM :: Text -> DecodeM a
mapErrors :: (BaseDecodeError -> BaseDecodeError) -> DecodeM a -> DecodeM a
addContext :: Span -> ContextItem -> DecodeM a -> DecodeM a
discardHints :: DecodeM a -> DecodeM a

Decoding errors

module KDL.Decoder.Internal.Error

DecodeM monad

data DecodeM a Source #

The monad that returns either a DecodeError or a result of type a.

Constructors

DecodeM_Found a DecodeHints
DecodeM_Fail (NonEmpty BaseDecodeError)

Instances

Instances details

Alternative DecodeM Source #
Instance details Defined in KDL.Decoder.Internal.DecodeM Methods empty :: DecodeM a # (<\|>) :: DecodeM a -> DecodeM a -> DecodeM a # some :: DecodeM a -> DecodeM [a] # many :: DecodeM a -> DecodeM [a] #
Applicative DecodeM Source #
Instance details Defined in KDL.Decoder.Internal.DecodeM Methods pure :: a -> DecodeM a # (<>) :: DecodeM (a -> b) -> DecodeM a -> DecodeM b # liftA2 :: (a -> b -> c) -> DecodeM a -> DecodeM b -> DecodeM c # (>) :: DecodeM a -> DecodeM b -> DecodeM b # (<*) :: DecodeM a -> DecodeM b -> DecodeM a #
Functor DecodeM Source #
Instance details Defined in KDL.Decoder.Internal.DecodeM Methods fmap :: (a -> b) -> DecodeM a -> DecodeM b # (<$) :: a -> DecodeM b -> DecodeM a #
Monad DecodeM Source #
Instance details Defined in KDL.Decoder.Internal.DecodeM Methods (>>=) :: DecodeM a -> (a -> DecodeM b) -> DecodeM b # (>>) :: DecodeM a -> DecodeM b -> DecodeM b # return :: a -> DecodeM a #

type DecodeHints = [BaseDecodeError] Source #

Hints to provide additional context in a future error after a successful branch.

Take this motivating example: a node takes an arbitrary number of string args. If you pass some strings then a number, it'll successfully parse up to the number and return success, only for the node to fail later with "unexpected argument: 123". But the true error was "unexpected number, expected string".

runDecodeM :: DecodeM a -> Either DecodeError a Source #

Run a DecodeM action and return the result or the deepest error found.

decodeThrow :: DecodeErrorKind -> DecodeM a Source #

Throw an error.

failM :: Text -> DecodeM a Source #

Throw a DecodeError_Custom error.

mapErrors :: (BaseDecodeError -> BaseDecodeError) -> DecodeM a -> DecodeM a Source #

addContext :: Span -> ContextItem -> DecodeM a -> DecodeM a Source #

Add context to all errors that occur in the given action.

discardHints :: DecodeM a -> DecodeM a Source #

Discard hints after validating that an error context is successful.