OptEnvConf.Reader

Documentation

newtype Reader a

Constructors

Reader

Fields

• unReader :: String -> Either String a

Instances

Applicative Reader

Defined in OptEnvConf.Reader

Methods

pure :: a -> Reader a

(<*>) :: Reader (a -> b) -> Reader a -> Reader b

liftA2 :: (a -> b -> c) -> Reader a -> Reader b -> Reader c

(*>) :: Reader a -> Reader b -> Reader b

(<*) :: Reader a -> Reader b -> Reader a

Functor Reader

Defined in OptEnvConf.Reader

Methods

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

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

Monad Reader

Defined in OptEnvConf.Reader

Methods

(>>=) :: Reader a -> (a -> Reader b) -> Reader b

(>>) :: Reader a -> Reader b -> Reader b

return :: a -> Reader a

MonadReader String Reader

Defined in OptEnvConf.Reader

Methods

ask :: Reader String

local :: (String -> String) -> Reader a -> Reader a

reader :: (String -> a) -> Reader a

Common readers

str :: IsString s => Reader s

Read a string as-is.

This is the reader you will want to use for reading a Value.

This is different from auto for strings because Read wants to parse quotes when parsing Strings.

auto :: Read a => Reader a

Read via the Read instance

You cannot use this for bare strings, because Read for strings parses quotes.

exists :: Reader Bool

Always return True

exists = Reader $ const $ pure True

viaCodec :: HasCodec a => Reader a

Constructing your own reader

maybeReader :: (String -> Maybe a) -> Reader a

Turn a Maybe parsing function into a Reader

eitherReader :: (String -> Either String a) -> Reader a

Turn an Either parsing function into a Reader

API note: This is a forward-compatible alias for Reader.

Comma-separated readers

commaSeparated :: Reader a -> Reader (NonEmpty a)

Turn a reader into one that parses comma separated values with that reader.

commaSeparatedList :: Reader a -> Reader [a]

Like commaSeparated but uses a list type.

Note that this will never parse the empty list, so prefer commaSeparated if you want a more accurately typed function.

commaSeparatedSet :: Ord a => Reader a -> Reader (Set a)

Like commaSeparated but uses a set type.

Note that this will never parse the empty list, so prefer commaSeparated if you want a more accurately typed function.

Note also that this function throws away any ordering information and ignores any duplicate values.

Internal

runReader :: Reader a -> String -> Either String a

renderCommaSeparated :: NonEmpty String -> String

Separate by commas and escape commas in values

parseCommaSeparated :: String -> NonEmpty String

Parse comma separated string, ignore escaped commas