{-# LANGUAGE PolyKinds #-}
module Servant.API.QueryParam where

-- | Lookup the value associated to the @sym@ query string parameter
-- and try to extract it as a value of type @a@.
--
-- Example:
--
-- > -- /books?author=<author name>
-- > type MyApi = "books" :> QueryParam "author" Text :> Get [Book]
data QueryParam sym a

-- | Lookup the values associated to the @sym@ query string parameter
-- and try to extract it as a value of type @[a]@. This is typically
-- meant to support query string parameters of the form
-- @param[]=val1&param[]=val2@ and so on. Note that servant doesn't actually
-- require the @[]@s and will fetch the values just fine with
-- @param=val1&param=val2@, too.
--
-- Example:
--
-- > -- /books?authors[]=<author1>&authors[]=<author2>&...
-- > type MyApi = "books" :> QueryParams "authors" Text :> Get [Book]
data QueryParams sym a

-- | Lookup a potentially value-less query string parameter
-- with boolean semantics. If the param @sym@ is there without any value,
-- or if it's there with value "true" or "1", it's interpreted as 'True'.
-- Otherwise, it's interpreted as 'False'.
--
-- Example:
--
-- > -- /books?published
-- > type MyApi = "books" :> QueryFlag "published" :> Get [Book]
data QueryFlag sym