EVP

Documentation

type Name = String

data Error

Constructors

Missing Name

ParseError Name String String

CustomError String

Instances

Show Error

Defined in EVP.Internal

Methods

showsPrec :: Int -> Error -> ShowS

show :: Error -> String

showList :: [Error] -> ShowS

Parsers

data Scan a

Instances

Applicative Scan

Defined in EVP.Internal

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

Defined in EVP.Internal

Methods

fmap :: (a -> b) -> Scan a -> Scan b

(<$) :: a -> Scan b -> Scan a

data Var a

Constructors

Var

Fields

• name :: Name
• defaultValue :: Maybe a
• metavar :: Maybe String

Instances

Typeable a => IsString (Var a)

Defined in EVP

Methods

fromString :: String -> Var a

Show a => Show (Var a)

Defined in EVP

Methods

showsPrec :: Int -> Var a -> ShowS

show :: Var a -> String

showList :: [Var a] -> ShowS

Eq a => Eq (Var a)

Defined in EVP

Methods

(==) :: Var a -> Var a -> Bool

(/=) :: Var a -> Var a -> Bool

string :: (IsString a, Show a, Typeable a) => Var a -> Scan a

Obtain the environment variable.

yaml :: forall a. (Show a, Typeable a, FromJSON a, ToJSON a) => Var a -> Scan a

Parse the environment variable as a YAML value.

parse :: Show a => Var a -> (String -> Either String a) -> Scan a

Parse the environment variable with a custom parser.

secret :: Scan a -> Scan a

Disable logging of parsed values.

group :: String -> Scan a -> Scan a

Give a name to a group of parsers.

defaultsTo :: Var a -> a -> Var a infixl 1

Provide a default value.

Runner

data Settings

Constructors

Settings

Fields

• parseLogger :: GroupStack -> Name -> String -> IO ()
• errorLogger :: GroupStack -> Error -> IO ()
• unusedLogger :: Name -> Maybe (IO ())
• pedantic :: Bool

  exit on warning

• helpFlag :: Maybe Name

  when an environment varialbe with this name is set, print the help message and exit

Instances

Default Settings

Defined in EVP

Methods

def :: Settings

def :: Default a => a

The default value for this type.

scan :: Scan a -> IO a

Parse environment variables with the default settings.

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

Parse environment variables with custom settings.

enumerate :: Scan a -> [Name]

Enumerate the names of the variables it would parse.

help :: Scan a -> String

Display the list of environment variables and their default values in the dotenv format.

Logger

type GroupStack = [String]

renderError :: Error -> String

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

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

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

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

Advanced

modifyError :: (Error -> Error) -> Scan a -> Scan a