{-# LANGUAGE DeriveGeneric #-}

module Dhall.Syntax.Binding
    ( Binding(..)
    , makeBinding

      -- * Optics
    , bindingExprs
    ) where

import                Data.Text         (Text)
import {-# SOURCE #-} Dhall.Syntax.Expr (Expr)
import                GHC.Generics      (Generic)

-- | Record the binding part of a @let@ expression.
--
-- For example,
--
-- > let {- A -} x {- B -} : {- C -} Bool = {- D -} True in x
--
-- … will be instantiated as follows:
--
-- * @bindingSrc0@ corresponds to the @A@ comment.
-- * @variable@ is @"x"@
-- * @bindingSrc1@ corresponds to the @B@ comment.
-- * @annotation@ is 'Just' a pair, corresponding to the @C@ comment and @Bool@.
-- * @bindingSrc2@ corresponds to the @D@ comment.
-- * @value@ corresponds to @True@.
data Binding s a = Binding
    { forall s a. Binding s a -> Maybe s
bindingSrc0 :: Maybe s
    , forall s a. Binding s a -> Text
variable    :: Text
    , forall s a. Binding s a -> Maybe s
bindingSrc1 :: Maybe s
    , forall s a. Binding s a -> Maybe (Maybe s, Expr s a)
annotation  :: Maybe (Maybe s, Expr s a)
    , forall s a. Binding s a -> Maybe s
bindingSrc2 :: Maybe s
    , forall s a. Binding s a -> Expr s a
value       :: Expr s a
    } deriving (forall x. Binding s a -> Rep (Binding s a) x)
-> (forall x. Rep (Binding s a) x -> Binding s a)
-> Generic (Binding s a)
forall x. Rep (Binding s a) x -> Binding s a
forall x. Binding s a -> Rep (Binding s a) x
forall a.
(forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
forall s a x. Rep (Binding s a) x -> Binding s a
forall s a x. Binding s a -> Rep (Binding s a) x
$cfrom :: forall s a x. Binding s a -> Rep (Binding s a) x
from :: forall x. Binding s a -> Rep (Binding s a) x
$cto :: forall s a x. Rep (Binding s a) x -> Binding s a
to :: forall x. Rep (Binding s a) x -> Binding s a
Generic

{-| Construct a 'Binding' with no source information and no type annotation.
-}
makeBinding :: Text -> Expr s a -> Binding s a
makeBinding :: forall s a. Text -> Expr s a -> Binding s a
makeBinding Text
name = Maybe s
-> Text
-> Maybe s
-> Maybe (Maybe s, Expr s a)
-> Maybe s
-> Expr s a
-> Binding s a
forall s a.
Maybe s
-> Text
-> Maybe s
-> Maybe (Maybe s, Expr s a)
-> Maybe s
-> Expr s a
-> Binding s a
Binding Maybe s
forall a. Maybe a
Nothing Text
name Maybe s
forall a. Maybe a
Nothing Maybe (Maybe s, Expr s a)
forall a. Maybe a
Nothing Maybe s
forall a. Maybe a
Nothing

{-| Traverse over the immediate 'Expr' children in a 'Binding'.
-}
bindingExprs
  :: (Applicative f)
  => (Expr s a -> f (Expr s b))
  -> Binding s a -> f (Binding s b)
bindingExprs :: forall (f :: * -> *) s a b.
Applicative f =>
(Expr s a -> f (Expr s b)) -> Binding s a -> f (Binding s b)
bindingExprs Expr s a -> f (Expr s b)
f (Binding Maybe s
s0 Text
n Maybe s
s1 Maybe (Maybe s, Expr s a)
t Maybe s
s2 Expr s a
v) =
  Maybe s
-> Text
-> Maybe s
-> Maybe (Maybe s, Expr s b)
-> Maybe s
-> Expr s b
-> Binding s b
forall s a.
Maybe s
-> Text
-> Maybe s
-> Maybe (Maybe s, Expr s a)
-> Maybe s
-> Expr s a
-> Binding s a
Binding
    (Maybe s
 -> Text
 -> Maybe s
 -> Maybe (Maybe s, Expr s b)
 -> Maybe s
 -> Expr s b
 -> Binding s b)
-> f (Maybe s)
-> f (Text
      -> Maybe s
      -> Maybe (Maybe s, Expr s b)
      -> Maybe s
      -> Expr s b
      -> Binding s b)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Maybe s -> f (Maybe s)
forall a. a -> f a
forall (f :: * -> *) a. Applicative f => a -> f a
pure Maybe s
s0
    f (Text
   -> Maybe s
   -> Maybe (Maybe s, Expr s b)
   -> Maybe s
   -> Expr s b
   -> Binding s b)
-> f Text
-> f (Maybe s
      -> Maybe (Maybe s, Expr s b) -> Maybe s -> Expr s b -> Binding s b)
forall a b. f (a -> b) -> f a -> f b
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> Text -> f Text
forall a. a -> f a
forall (f :: * -> *) a. Applicative f => a -> f a
pure Text
n
    f (Maybe s
   -> Maybe (Maybe s, Expr s b) -> Maybe s -> Expr s b -> Binding s b)
-> f (Maybe s)
-> f (Maybe (Maybe s, Expr s b)
      -> Maybe s -> Expr s b -> Binding s b)
forall a b. f (a -> b) -> f a -> f b
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> Maybe s -> f (Maybe s)
forall a. a -> f a
forall (f :: * -> *) a. Applicative f => a -> f a
pure Maybe s
s1
    f (Maybe (Maybe s, Expr s b) -> Maybe s -> Expr s b -> Binding s b)
-> f (Maybe (Maybe s, Expr s b))
-> f (Maybe s -> Expr s b -> Binding s b)
forall a b. f (a -> b) -> f a -> f b
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> ((Maybe s, Expr s a) -> f (Maybe s, Expr s b))
-> Maybe (Maybe s, Expr s a) -> f (Maybe (Maybe s, Expr s b))
forall (t :: * -> *) (f :: * -> *) a b.
(Traversable t, Applicative f) =>
(a -> f b) -> t a -> f (t b)
forall (f :: * -> *) a b.
Applicative f =>
(a -> f b) -> Maybe a -> f (Maybe b)
traverse ((Expr s a -> f (Expr s b))
-> (Maybe s, Expr s a) -> f (Maybe s, Expr s b)
forall (t :: * -> *) (f :: * -> *) a b.
(Traversable t, Applicative f) =>
(a -> f b) -> t a -> f (t b)
forall (f :: * -> *) a b.
Applicative f =>
(a -> f b) -> (Maybe s, a) -> f (Maybe s, b)
traverse Expr s a -> f (Expr s b)
f) Maybe (Maybe s, Expr s a)
t
    f (Maybe s -> Expr s b -> Binding s b)
-> f (Maybe s) -> f (Expr s b -> Binding s b)
forall a b. f (a -> b) -> f a -> f b
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> Maybe s -> f (Maybe s)
forall a. a -> f a
forall (f :: * -> *) a. Applicative f => a -> f a
pure Maybe s
s2
    f (Expr s b -> Binding s b) -> f (Expr s b) -> f (Binding s b)
forall a b. f (a -> b) -> f a -> f b
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> Expr s a -> f (Expr s b)
f Expr s a
v
{-# INLINABLE bindingExprs #-}