generic-env-0.1.1.0: Generic Environment Generator

Safe Haskell	Safe
Language	Haskell2010

GenericEnv

Synopsis

fromEnv :: forall env. (Generic env, Envable (Rep env)) => EnvOptions -> IO (Either String env)
data EnvOptions = EnvOptions {
- modifyFieldNames :: String -> String
- envKeyPrefix :: String
}
defaultEnvOptions :: EnvOptions
withPrefix :: String -> EnvOptions

Documentation

fromEnv :: forall env. (Generic env, Envable (Rep env)) => EnvOptions -> IO (Either String env) Source #

Tries to produce type env from the environment variables. The Envable restriction is for ensuring type is a record-syntaxed product type.

data EnvOptions Source #

Constructors

Fields

modifyFieldNames :: String -> String
Field names of the type can be modified. For a type:
```
  data MyEnv { _eName :: String, _eCount :: Int }
```
you may want to eliminate the prefixes beforehand. Then options would be:
```
  defaultOptions { modifyFieldNames = drop 2 }
```
envKeyPrefix :: String
Prefix for the environment variable keys. If your type is
```
  data MyEnv { name :: String, count :: Int }
```
you might be using environment variables like the following:
```
  APP_NAME=genericenv
  APP_COUNT=3
```
The prefix should be APP_ in this case.

defaultEnvOptions :: EnvOptions Source #

withPrefix :: String -> EnvOptions Source #

This function is for generating the most common use case. Only sets the prefix over the default env options.