Data.Configurator.Parser

A set of combinators for high-level configuration parsing.

Documentation

class Applicative m => ConfigParser m

The ConfigParser type class abstracts over ConfigParserM and ConfigParserA. This is intended to be a closed typeclass, without any additional instances.

Instances

ConfigParser ConfigParserA

ConfigParser ConfigParserM

data ConfigParserA a

A ConfigParserM a computation produces a value of type Maybe a from a given Config, in addition to a list of diagnostic messages. After executing a subcomputation that returns a Nothing value, computations of type ConfigParserA will continue to run in order to produce more error messages. For this reason, ConfigParserA does not have a proper Monad instance. (But see unsafeBind)

Instances

Functor ConfigParserA

Typeable1 ConfigParserA

Applicative ConfigParserA

ConfigParser ConfigParserA

data ConfigParserM a

A ConfigParserM a computation produces a value of type Maybe a from a given Config, in addition to a list of diagnostic messages which may be interpreted as warnings or errors as deemed appropriate. If the value returned by a computation is Nothing, then no subsequent actions (e.g. via <*> or >>=) will be performed.

Instances

Monad ConfigParserM

Functor ConfigParserM

Typeable1 ConfigParserM

Applicative ConfigParserM

ConfigParser ConfigParserM

data ConfigError

An error (or warning) from a higher-level parser of a configuration file.

Constructors

ConfigError

Fields

configErrorLocation :: ConfigErrorLocation

configConversionError :: Maybe [ConversionError]

Instances

Eq ConfigError

Show ConfigError

Typeable ConfigError

Exception ConfigError

data ConfigErrorLocation

Constructors

KeyMissing [Name]

Key FilePath Name

Instances

Eq ConfigErrorLocation

Show ConfigErrorLocation

Typeable ConfigErrorLocation

data ConversionError

Constructors

ConversionError

Fields

conversionErrorLoc :: Text

conversionErrorWhy :: ConversionErrorWhy

conversionErrorVal :: !(Maybe Value)

conversionErrorType :: !(Maybe TypeRep)

conversionErrorMsg :: !(Maybe Text)

Instances

Eq ConversionError

Show ConversionError

Typeable ConversionError

Exception ConversionError

data ConversionErrorWhy

Constructors

MissingValue

ExtraValues

ExhaustedValues

TypeError

ValueError

MonadFail

OtherError

Instances

Eq ConversionErrorWhy

Show ConversionErrorWhy

Typeable ConversionErrorWhy

data Config

A Config is a finite map from Text to Value.

data ConfigTransform

Conceptually, a ConfigTransform is a function Config -> Config. It's a restricted subset of such functions as to preserve the possibility of reliable dependency tracking in later versions of configurator-ng.

Instances

Monoid ConfigTransform

mempty is the identity ConfigTransform, mappend is the composition of two ConfigTransforms.

unsafeBind :: ConfigParserA a -> (a -> ConfigParserA b) -> ConfigParserA b

The purpose of this function is to make it convenient to use do-notation with ConfigParserA, either by defining a Monad instance or locally rebinding '(>>=)'. Be warned that this is an abuse, and incorrect usage can result in exceptions. A safe way to use this function would be to treat is as applicative-do notation. A safer alternative would be to use the ApplicativeDo language extension available in GHC 8.0 and not use this function at all.

runParser :: ConfigParser m => m a -> Config -> (Maybe a, [ConfigError])

runParserA :: ConfigParserA a -> Config -> (Maybe a, [ConfigError])

Exactly the same as runParser, except less polymorphic

runParserM :: ConfigParserM a -> Config -> (Maybe a, [ConfigError])

Exactly the same as runParser, except less polymorphic

parserA :: ConfigParser m => ConfigParserA a -> m a

Lift a ConfigParserA action into a generic ConfigParser action. Note that this does not change the semantics of the argument, it just allows a ConfigParserA computation to be embedded in another ConfigParser computation of either variant.

parserM :: ConfigParser m => ConfigParserM a -> m a

Lift a ConfigParserM action into a generic ConfigParser action. Note that this does not change the semantics of the argument, it just allows a ConfigParserM computation to be embedded in another ConfigParser computation of either variant.

subassocs :: ConfigParser m => Name -> m [(Name, Value)]

subassocs' :: ConfigParser m => Name -> m [(Name, Value)]

subgroups :: ConfigParser m => Name -> m [Name]

localConfig :: ConfigParser m => ConfigTransform -> m a -> m a

Modifies the Config that a subparser is operating on. This is perfectly analogous to local.

union :: ConfigTransform -> ConfigTransform -> ConfigTransform

subconfig :: Text -> ConfigTransform -> ConfigTransform

superconfig :: Text -> ConfigTransform -> ConfigTransform

recover :: ConfigParser m => m a -> m (Maybe a)

Given the expression recover action, the action will be run, and if it returns no value, recover action will return Nothing. If action returns the value a, then recover action will return the value Just a. Any errors or warnings are passed through as-is.

key :: (ConfigParser m, FromMaybeValue a) => Name -> m a

keyWith :: ConfigParser m => Name -> MaybeParser a -> m a