Usage
----
[](https://hackage.haskell.org/package/panfiguration)
Panfiguration is a library that provides a composable, automatically-derived interface for configuration parameters.
Currently three backends are supported; `envs` for environment variables, `opts` for command-line options and `defaults` for default values.
The `Monoid` instance makes these backends composable. See the example below for the basic usage.
Example
----
```haskell
import Barbies.TH
import Panfiguration
passthroughBareB [d|
data ServerArgs = ServerArgs
{ http_host :: String
, http_port :: Int
, enable_service_log :: Bool
, environment :: String
}
|]
getServerArgs :: IO ServerArgs
getServerArgs = run $ mconcat
[ logger putStrLn
, declCase snake
, envs `withNames` \names -> names
{ http_host = "HTTP_HOST"
, http_port = "HTTP_PORT"
}
, opts `asCase` kebab
, defaults ServerArgs
{ http_host = Just "0.0.0.0"
, http_port = Just 8080
, enable_service_log = Just True
, environment = Nothing -- required parameter
}
]
```
Naming conventions
----
`declCase` specifies the naming convention of the Haskell data declaration (the default is `camel`).
The naming conventions are configurable by the `asCase` modifier.
By default, `envs` and `opts` uses SNAKE_CASE and kebab-case respectively.
The following styles are supported:
```haskell
AsIs
Camel
camel
snake
SNAKE
kebab
KEBAB
Prefixed <str>
```
You can also override individual names directly by `withNames`.