-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Template Haskell helpers for highjson specs
--   
--   Template Haskell helpers for highjson specs
@package highjson-th
@version 0.4.0.0

module Data.HighJson.TH
deriveJsonSwagger :: Name -> Name -> Q [Dec]
jsonSerializer :: AllHave ToJSON as => HighSpec a ty as -> a -> Value
jsonEncoder :: AllHave ToJSON as => HighSpec a ty as -> a -> Encoding
jsonParser :: AllHave FromJSON as => HighSpec a ty as -> Value -> Parser a

-- | Automatically generate a <a>NamedSchema</a> from a <a>HighSpec</a>
makeDeclareNamedSchema :: (AllHave ToSchema ts, AllHave ToJSON ts, IsValidSwaggerType ty ts) => HighSpec k ty ts -> f k -> DeclM NamedSchema

-- | Convert a type into <tt><a>Schema</a></tt>.
--   
--   An example type and instance:
--   
--   <pre>
--   {-# LANGUAGE OverloadedStrings #-}   -- allows to write <a>Text</a> literals
--   {-# LANGUAGE OverloadedLists #-}     -- allows to write <a>Map</a> and <a>HashMap</a> as lists
--   
--   import Control.Lens
--   import Data.Proxy
--   import Data.Swagger
--   
--   data Coord = Coord { x :: Double, y :: Double }
--   
--   instance ToSchema Coord where
--     declareNamedSchema _ = do
--       doubleSchema &lt;- declareSchemaRef (Proxy :: Proxy Double)
--       return $ NamedSchema (Just "Coord") $ mempty
--         &amp; type_ .~ SwaggerObject
--         &amp; properties .~
--             [ ("x", doubleSchema)
--             , ("y", doubleSchema)
--             ]
--         &amp; required .~ [ "x", "y" ]
--   </pre>
--   
--   Instead of manually writing your <tt><a>ToSchema</a></tt> instance you
--   can use a default generic implementation of
--   <tt><a>declareNamedSchema</a></tt>.
--   
--   To do that, simply add <tt>deriving <a>Generic</a></tt> clause to your
--   datatype and declare a <tt><a>ToSchema</a></tt> instance for your
--   datatype without giving definition for
--   <tt><a>declareNamedSchema</a></tt>.
--   
--   For instance, the previous example can be simplified into this:
--   
--   <pre>
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import GHC.Generics (Generic)
--   
--   data Coord = Coord { x :: Double, y :: Double } deriving Generic
--   
--   instance ToSchema Coord
--   </pre>
class ToSchema a

-- | Convert a type into an optionally named schema together with all used
--   definitions. Note that the schema itself is included in definitions
--   only if it is recursive (and thus needs its definition in scope).
declareNamedSchema :: ToSchema a => proxy a -> Declare Definitions Schema NamedSchema

-- | A type that can be converted to JSON.
--   
--   Instances in general <i>must</i> specify <a>toJSON</a> and
--   <i>should</i> (but don't need to) specify <a>toEncoding</a>.
--   
--   An example type and instance:
--   
--   <pre>
--   -- Allow ourselves to write <a>Text</a> literals.
--   {-# LANGUAGE OverloadedStrings #-}
--   
--   data Coord = Coord { x :: Double, y :: Double }
--   
--   instance <a>ToJSON</a> Coord where
--     <a>toJSON</a> (Coord x y) = <a>object</a> ["x" <a>.=</a> x, "y" <a>.=</a> y]
--   
--     <a>toEncoding</a> (Coord x y) = <tt>pairs</tt> ("x" <a>.=</a> x <a>&lt;&gt;</a> "y" <a>.=</a> y)
--   </pre>
--   
--   Instead of manually writing your <a>ToJSON</a> instance, there are two
--   options to do it automatically:
--   
--   <ul>
--   <li><a>Data.Aeson.TH</a> provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.</li>
--   <li>The compiler can provide a default generic implementation for
--   <a>toJSON</a>.</li>
--   </ul>
--   
--   To use the second, simply add a <tt>deriving <a>Generic</a></tt>
--   clause to your datatype and declare a <a>ToJSON</a> instance. If you
--   require nothing other than <a>defaultOptions</a>, it is sufficient to
--   write (and this is the only alternative where the default
--   <a>toJSON</a> implementation is sufficient):
--   
--   <pre>
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import <a>GHC.Generics</a>
--   
--   data Coord = Coord { x :: Double, y :: Double } deriving <a>Generic</a>
--   
--   instance <a>ToJSON</a> Coord where
--       <a>toEncoding</a> = <a>genericToEncoding</a> <a>defaultOptions</a>
--   </pre>
--   
--   If on the other hand you wish to customize the generic decoding, you
--   have to implement both methods:
--   
--   <pre>
--   customOptions = <a>defaultOptions</a>
--                   { <a>fieldLabelModifier</a> = <a>map</a> <a>toUpper</a>
--                   }
--   
--   instance <a>ToJSON</a> Coord where
--       <a>toJSON</a>     = <a>genericToJSON</a> customOptions
--       <a>toEncoding</a> = <a>genericToEncoding</a> customOptions
--   </pre>
--   
--   Previous versions of this library only had the <a>toJSON</a> method.
--   Adding <a>toEncoding</a> had to reasons:
--   
--   <ol>
--   <li>toEncoding is more efficient for the common case that the output
--   of <a>toJSON</a> is directly serialized to a <tt>ByteString</tt>.
--   Further, expressing either method in terms of the other would be
--   non-optimal.</li>
--   <li>The choice of defaults allows a smooth transition for existing
--   users: Existing instances that do not define <a>toEncoding</a> still
--   compile and have the correct semantics. This is ensured by making the
--   default implementation of <a>toEncoding</a> use <a>toJSON</a>. This
--   produces correct results, but since it performs an intermediate
--   conversion to a <a>Value</a>, it will be less efficient than directly
--   emitting an <a>Encoding</a>. (this also means that specifying nothing
--   more than <tt>instance ToJSON Coord</tt> would be sufficient as a
--   generically decoding instance, but there probably exists no good
--   reason to not specify <a>toEncoding</a> in new instances.)</li>
--   </ol>
class ToJSON a

-- | Convert a Haskell value to a JSON-friendly intermediate type.
toJSON :: ToJSON a => a -> Value

-- | Encode a Haskell value as JSON.
--   
--   The default implementation of this method creates an intermediate
--   <a>Value</a> using <a>toJSON</a>. This provides source-level
--   compatibility for people upgrading from older versions of this
--   library, but obviously offers no performance advantage.
--   
--   To benefit from direct encoding, you <i>must</i> provide an
--   implementation for this method. The easiest way to do so is by having
--   your types implement <a>Generic</a> using the <tt>DeriveGeneric</tt>
--   extension, and then have GHC generate a method body as follows.
--   
--   <pre>
--   instance <a>ToJSON</a> Coord where
--       <a>toEncoding</a> = <a>genericToEncoding</a> <a>defaultOptions</a>
--   </pre>
toEncoding :: ToJSON a => a -> Encoding
toJSONList :: ToJSON a => [a] -> Value
toEncodingList :: ToJSON a => [a] -> Encoding

-- | A type that can be converted from JSON, with the possibility of
--   failure.
--   
--   In many cases, you can get the compiler to generate parsing code for
--   you (see below). To begin, let's cover writing an instance by hand.
--   
--   There are various reasons a conversion could fail. For example, an
--   <a>Object</a> could be missing a required key, an <a>Array</a> could
--   be of the wrong size, or a value could be of an incompatible type.
--   
--   The basic ways to signal a failed conversion are as follows:
--   
--   <ul>
--   <li><tt>empty</tt> and <tt>mzero</tt> work, but are terse and
--   uninformative;</li>
--   <li><a>fail</a> yields a custom error message;</li>
--   <li><a>typeMismatch</a> produces an informative message for cases when
--   the value encountered is not of the expected type.</li>
--   </ul>
--   
--   An example type and instance using <a>typeMismatch</a>:
--   
--   <pre>
--   -- Allow ourselves to write <a>Text</a> literals.
--   {-# LANGUAGE OverloadedStrings #-}
--   
--   data Coord = Coord { x :: Double, y :: Double }
--   
--   instance <a>FromJSON</a> Coord where
--       <a>parseJSON</a> (<a>Object</a> v) = Coord
--           <a>&lt;$&gt;</a> v <a>.:</a> "x"
--           <a>&lt;*&gt;</a> v <a>.:</a> "y"
--   
--       -- We do not expect a non-<a>Object</a> value here.
--       -- We could use <tt>mzero</tt> to fail, but <a>typeMismatch</a>
--       -- gives a much more informative error message.
--       <a>parseJSON</a> invalid    = <a>typeMismatch</a> "Coord" invalid
--   </pre>
--   
--   For this common case of only being concerned with a single type of
--   JSON value, the functions <a>withObject</a>, <a>withNumber</a>, etc.
--   are provided. Their use is to be preferred when possible, since they
--   are more terse. Using <a>withObject</a>, we can rewrite the above
--   instance (assuming the same language extension and data type) as:
--   
--   <pre>
--   instance <a>FromJSON</a> Coord where
--       <a>parseJSON</a> = <a>withObject</a> "Coord" $ \v -&gt; Coord
--           <a>&lt;$&gt;</a> v <a>.:</a> "x"
--           <a>&lt;*&gt;</a> v <a>.:</a> "y"
--   </pre>
--   
--   Instead of manually writing your <a>FromJSON</a> instance, there are
--   two options to do it automatically:
--   
--   <ul>
--   <li><a>Data.Aeson.TH</a> provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.</li>
--   <li>The compiler can provide a default generic implementation for
--   <a>parseJSON</a>.</li>
--   </ul>
--   
--   To use the second, simply add a <tt>deriving <a>Generic</a></tt>
--   clause to your datatype and declare a <a>FromJSON</a> instance for
--   your datatype without giving a definition for <a>parseJSON</a>.
--   
--   For example, the previous example can be simplified to just:
--   
--   <pre>
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import <a>GHC.Generics</a>
--   
--   data Coord = Coord { x :: Double, y :: Double } deriving <a>Generic</a>
--   
--   instance <a>FromJSON</a> Coord
--   </pre>
--   
--   The default implementation will be equivalent to <tt>parseJSON =
--   <a>genericParseJSON</a> <a>defaultOptions</a></tt>; If you need
--   different options, you can customize the generic decoding by defining:
--   
--   <pre>
--   customOptions = <a>defaultOptions</a>
--                   { <a>fieldLabelModifier</a> = <a>map</a> <a>toUpper</a>
--                   }
--   
--   instance <a>FromJSON</a> Coord where
--       <a>parseJSON</a> = <a>genericParseJSON</a> customOptions
--   </pre>
class FromJSON a
parseJSON :: FromJSON a => Value -> Parser a
parseJSONList :: FromJSON a => Value -> Parser [a]
