Safe Haskell	Safe-Inferred
Language	GHC2021

EVP

Contents

Parsers
Providing a default value
Runner
Logger
Internal

Synopsis

type Name = String
data Error
- = Missing Name
- | ParseError Name String
string :: IsString a => Name -> Scan a
yaml :: (Show a, FromJSON a) => Name -> Scan a
parse :: Show a => Name -> (String -> Either String a) -> Scan a
secret :: Scan a -> Scan a
stringDefault :: IsString a => Name -> String -> Scan a
yamlDefault :: (Show a, FromJSON a) => Name -> a -> Scan a
parseDefault :: Show a => Name -> a -> (String -> Either String a) -> Scan a
data Settings = Settings {
- parseLogger :: Name -> String -> IO ()
- errorLogger :: Error -> IO ()
- unusedLogger :: Name -> Maybe (IO ())
- pedantic :: Bool
}
def :: Default a => a
scan :: Scan a -> IO a
scanWith :: Settings -> Scan a -> IO a
enumerate :: Scan a -> [Name]
assumePrefix :: String -> Name -> Maybe (IO ())
obsolete :: [Name] -> Name -> Maybe (IO ())
data Scan a where
- Pure :: a -> Scan a
- Var :: Name -> (Maybe String -> Either Error (String, a)) -> Scan (a -> b) -> Scan b

Documentation

type Name = String Source #

data Error Source #

Constructors

Missing Name
ParseError Name String

Instances

Instances details

Show Error Source #
Instance details Defined in EVP Methods showsPrec :: Int -> Error -> ShowS # show :: Error -> String # showList :: [Error] -> ShowS #

Parsers

string :: IsString a => Name -> Scan a Source #

Obtain the environment variable.

yaml :: (Show a, FromJSON a) => Name -> Scan a Source #

Parse the environment variable as a YAML value.

parse :: Show a => Name -> (String -> Either String a) -> Scan a Source #

secret :: Scan a -> Scan a Source #

Disable logging of parsed values.

Providing a default value

stringDefault :: IsString a => Name -> String -> Scan a Source #

yamlDefault :: (Show a, FromJSON a) => Name -> a -> Scan a Source #

Parse the environment variable as a YAML value.

parseDefault :: Show a => Name -> a -> (String -> Either String a) -> Scan a Source #

Runner

data Settings Source #

Constructors

Settings
Fields parseLogger :: Name -> String -> IO () errorLogger :: Error -> IO () unusedLogger :: Name -> Maybe (IO ()) pedantic :: Bool exit on warning

Instances

Instances details

Default Settings Source #
Instance details Defined in EVP Methods def :: Settings #

def :: Default a => a #

scan :: Scan a -> IO a Source #

scanWith :: Settings -> Scan a -> IO a Source #

enumerate :: Scan a -> [Name] Source #

Enumerate the names of the variables it would parse.

Logger

assumePrefix :: String -> Name -> Maybe (IO ()) Source #

Custom logging function for unusedLogger. assumePrefix p prints a warning for each unused environment variable prefixed by p.

obsolete :: [Name] -> Name -> Maybe (IO ()) Source #

obsolete names prints a warning if any of the names is set but not used.

Internal

data Scan a where Source #

Constructors

Pure :: a -> Scan a
Var :: Name -> (Maybe String -> Either Error (String, a)) -> Scan (a -> b) -> Scan b

Instances

Instances details

Applicative Scan Source #
Instance details Defined in EVP Methods pure :: a -> Scan a # (<>) :: Scan (a -> b) -> Scan a -> Scan b # liftA2 :: (a -> b -> c) -> Scan a -> Scan b -> Scan c # (>) :: Scan a -> Scan b -> Scan b # (<*) :: Scan a -> Scan b -> Scan a #
Functor Scan Source #
Instance details Defined in EVP Methods fmap :: (a -> b) -> Scan a -> Scan b # (<$) :: a -> Scan b -> Scan a #