System.Environment.Parser.FromEnv

Types which can be deserialized from an environment variable.

Documentation

class FromEnv a where

Types instantiatiating FromEnv can be deserialized from the environment directly.

Methods

parseEnv :: String -> Either String a

fromEnv :: Env r => r String -> r a

For this most part this should be left as default. It's useful for introducing non-failing parsers, though.

Instances

FromEnv Double

FromEnv Int

FromEnv Int8

FromEnv Int16

FromEnv Int32

FromEnv Int64

FromEnv Integer

FromEnv String

FromEnv ByteString

FromEnv ByteString

FromEnv Number

FromEnv Text

FromEnv UTCTime

Assumes first that the date is formatted as the W3C Profile of ISO 8601 but also implements a few other formats.

 %Y-%m-%dT%H:%M:%S%Q%z

 1997-07-16T19:20:30.45+01:00
 1997-07-16T19:20:30.45Z
 1997-07-16T19:20:30Z

 %a %b %_d %H:%M:%S %z %Y

 Sat Jan 18 22:20:02 +0000 2014
 Sat Jan 18 22:20:02 2014
 Jan 18 22:20:02 2014

FromEnv Value

FromEnv Text

FromEnv NominalDiffTime

Interprets a string as a decimal number of seconds

FromEnv Day

Parses the Gregorian calendar format "%Y-%m-%d".

FromEnv DiffTime

Interprets a string as a decimal number of seconds

FromEnv DBConnection

FromEnv Base16

FromEnv Base64Url

FromEnv Base64