{-# language QuasiQuotes #-}
{-# language TemplateHaskell #-}

{-# options_ghc -Wno-missing-fields #-}
{-# options_ghc -Wno-name-shadowing #-}

module Nix.TH where

import           Data.Fix                       ( Fix(unFix) )
import           Data.Generics.Aliases          ( extQ )
import qualified Data.Set                      as Set
import           Language.Haskell.TH
import qualified Language.Haskell.TH.Syntax    as TH
import           Language.Haskell.TH.Quote
import           Nix.Atoms
import           Nix.Expr.Types
import           Nix.Expr.Types.Annotated
import           Nix.Parser

quoteExprExp :: String -> ExpQ
quoteExprExp :: String -> ExpQ
quoteExprExp String
s =
  do
    NExpr
expr <- Text -> Q NExpr
forall (m :: * -> *). MonadFail m => Text -> m NExpr
parseExpr (Text -> Q NExpr) -> Text -> Q NExpr
forall a b. (a -> b) -> a -> b
$ String -> Text
forall a. IsString a => String -> a
fromString String
s
    (forall b. Data b => b -> Maybe ExpQ) -> NExpr -> ExpQ
forall (m :: * -> *) a.
(Quote m, Data a) =>
(forall b. Data b => b -> Maybe (m Exp)) -> a -> m Exp
dataToExpQ
      ((Set VarName -> NExprLoc -> Maybe ExpQ) -> NExpr -> b -> Maybe ExpQ
forall b loc q.
(Typeable b, Typeable loc) =>
(Set VarName -> loc -> Maybe q) -> NExpr -> b -> Maybe q
extQOnFreeVars Set VarName -> NExprLoc -> Maybe ExpQ
metaExp NExpr
expr (b -> Maybe ExpQ) -> (Text -> Maybe ExpQ) -> b -> Maybe ExpQ
forall a b q.
(Typeable a, Typeable b) =>
(a -> q) -> (b -> q) -> a -> q
`extQ` (ExpQ -> Maybe ExpQ
forall (f :: * -> *) a. Applicative f => a -> f a
pure (ExpQ -> Maybe ExpQ) -> (Text -> ExpQ) -> Text -> Maybe ExpQ
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Text -> ExpQ
forall t (m :: * -> *). (Lift t, Quote m) => t -> m Exp
TH.lift :: Text -> Q Exp)))
      NExpr
expr

quoteExprPat :: String -> PatQ
quoteExprPat :: String -> PatQ
quoteExprPat String
s =
  do
    NExpr
expr <- Text -> Q NExpr
forall (m :: * -> *). MonadFail m => Text -> m NExpr
parseExpr (Text -> Q NExpr) -> Text -> Q NExpr
forall a b. (a -> b) -> a -> b
$ String -> Text
forall a. IsString a => String -> a
fromString String
s
    (forall b. Data b => b -> Maybe PatQ) -> NExpr -> PatQ
forall (m :: * -> *) a.
(Quote m, Data a) =>
(forall b. Data b => b -> Maybe (m Pat)) -> a -> m Pat
dataToPatQ
      ((Set VarName -> NExprLoc -> Maybe PatQ) -> NExpr -> b -> Maybe PatQ
forall b loc q.
(Typeable b, Typeable loc) =>
(Set VarName -> loc -> Maybe q) -> NExpr -> b -> Maybe q
extQOnFreeVars Set VarName -> NExprLoc -> Maybe PatQ
metaPat NExpr
expr)
      NExpr
expr

-- | Helper function.
extQOnFreeVars
  :: ( Typeable b
    , Typeable loc
    )
  => ( Set VarName
    -> loc
    -> Maybe q
    )
  -> NExpr
  -> b
  -> Maybe q
extQOnFreeVars :: forall b loc q.
(Typeable b, Typeable loc) =>
(Set VarName -> loc -> Maybe q) -> NExpr -> b -> Maybe q
extQOnFreeVars Set VarName -> loc -> Maybe q
f = (b -> Maybe q) -> (loc -> Maybe q) -> b -> Maybe q
forall a b q.
(Typeable a, Typeable b) =>
(a -> q) -> (b -> q) -> a -> q
extQ (Maybe q -> b -> Maybe q
forall a b. a -> b -> a
const Maybe q
forall a. Maybe a
Nothing) ((loc -> Maybe q) -> b -> Maybe q)
-> (NExpr -> loc -> Maybe q) -> NExpr -> b -> Maybe q
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Set VarName -> loc -> Maybe q
f (Set VarName -> loc -> Maybe q)
-> (NExpr -> Set VarName) -> NExpr -> loc -> Maybe q
forall b c a. (b -> c) -> (a -> b) -> a -> c
. NExpr -> Set VarName
freeVars

parseExpr :: (MonadFail m) => Text -> m NExpr
parseExpr :: forall (m :: * -> *). MonadFail m => Text -> m NExpr
parseExpr =
  (Doc Void -> m NExpr)
-> (NExpr -> m NExpr) -> Either (Doc Void) NExpr -> m NExpr
forall a c b. (a -> c) -> (b -> c) -> Either a b -> c
either
    (String -> m NExpr
forall (m :: * -> *) a. MonadFail m => String -> m a
fail (String -> m NExpr) -> (Doc Void -> String) -> Doc Void -> m NExpr
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Doc Void -> String
forall b a. (Show a, IsString b) => a -> b
show)
    NExpr -> m NExpr
forall (f :: * -> *) a. Applicative f => a -> f a
pure
    (Either (Doc Void) NExpr -> m NExpr)
-> (Text -> Either (Doc Void) NExpr) -> Text -> m NExpr
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Text -> Either (Doc Void) NExpr
parseNixText

freeVars :: NExpr -> Set VarName
freeVars :: NExpr -> Set VarName
freeVars NExpr
e = case NExpr -> NExprF NExpr
forall (f :: * -> *). Fix f -> f (Fix f)
unFix NExpr
e of
  (NConstant    NAtom
_               ) -> Set VarName
forall a. Monoid a => a
mempty
  (NStr         NString NExpr
string          ) -> NString NExpr -> Set VarName
forall (t :: * -> *). Foldable t => t NExpr -> Set VarName
mapFreeVars NString NExpr
string
  (NSym         VarName
var             ) -> OneItem (Set VarName) -> Set VarName
forall x. One x => OneItem x -> x
one OneItem (Set VarName)
VarName
var
  (NList        [NExpr]
list            ) -> [NExpr] -> Set VarName
forall (t :: * -> *). Foldable t => t NExpr -> Set VarName
mapFreeVars [NExpr]
list
  (NSet   Recursivity
NonRecursive  [Binding NExpr]
bindings) -> [Binding NExpr] -> Set VarName
forall (t :: * -> *).
Foldable t =>
t (Binding NExpr) -> Set VarName
bindFreeVars [Binding NExpr]
bindings
  (NSet   Recursivity
Recursive     [Binding NExpr]
bindings) -> ([Binding NExpr] -> Set VarName)
-> ([Binding NExpr] -> Set VarName)
-> [Binding NExpr]
-> Set VarName
forall a.
(a -> Set VarName) -> (a -> Set VarName) -> a -> Set VarName
diffBetween [Binding NExpr] -> Set VarName
forall (t :: * -> *).
Foldable t =>
t (Binding NExpr) -> Set VarName
bindFreeVars [Binding NExpr] -> Set VarName
forall (t :: * -> *).
Foldable t =>
t (Binding NExpr) -> Set VarName
bindDefs [Binding NExpr]
bindings
  (NLiteralPath Path
_               ) -> Set VarName
forall a. Monoid a => a
mempty
  (NEnvPath     Path
_               ) -> Set VarName
forall a. Monoid a => a
mempty
  (NUnary       NUnaryOp
_    NExpr
expr       ) -> NExpr -> Set VarName
freeVars NExpr
expr
  (NBinary      NBinaryOp
_    NExpr
left NExpr
right ) -> NExpr -> NExpr -> Set VarName
collectFreeVars NExpr
left NExpr
right
  (NSelect      Maybe NExpr
orExpr NExpr
expr NAttrPath NExpr
path) ->
    [Set VarName] -> Set VarName
forall (f :: * -> *) a. (Foldable f, Ord a) => f (Set a) -> Set a
Set.unions
      [ NExpr -> Set VarName
freeVars NExpr
expr
      , NAttrPath NExpr -> Set VarName
pathFree NAttrPath NExpr
path
      , NExpr -> Set VarName
freeVars (NExpr -> Set VarName) -> Maybe NExpr -> Set VarName
forall b a. Monoid b => (a -> b) -> Maybe a -> b
`whenJust` Maybe NExpr
orExpr
      ]
  (NHasAttr NExpr
expr            NAttrPath NExpr
path) -> NExpr -> Set VarName
freeVars NExpr
expr Set VarName -> Set VarName -> Set VarName
forall a. Semigroup a => a -> a -> a
<> NAttrPath NExpr -> Set VarName
pathFree NAttrPath NExpr
path
  (NAbs     (Param VarName
varname) NExpr
expr) -> VarName -> Set VarName -> Set VarName
forall a. Ord a => a -> Set a -> Set a
Set.delete VarName
varname (NExpr -> Set VarName
freeVars NExpr
expr)
  (NAbs (ParamSet Maybe VarName
varname Variadic
_ ParamSet NExpr
pset) NExpr
expr) ->
    -- Include all free variables from the expression and the default arguments
    NExpr -> Set VarName
freeVars NExpr
expr Set VarName -> Set VarName -> Set VarName
forall a. Semigroup a => a -> a -> a
<>
    -- But remove the argument name if existing, and all arguments in the parameter set
    Set VarName -> Set VarName -> Set VarName
forall a. Ord a => Set a -> Set a -> Set a
Set.difference
      ([Set VarName] -> Set VarName
forall (f :: * -> *) a. (Foldable f, Ord a) => f (Set a) -> Set a
Set.unions ([Set VarName] -> Set VarName) -> [Set VarName] -> Set VarName
forall a b. (a -> b) -> a -> b
$ NExpr -> Set VarName
freeVars (NExpr -> Set VarName) -> [NExpr] -> [Set VarName]
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> ((VarName, Maybe NExpr) -> Maybe NExpr)
-> ParamSet NExpr -> [NExpr]
forall a b. (a -> Maybe b) -> [a] -> [b]
mapMaybe (VarName, Maybe NExpr) -> Maybe NExpr
forall a b. (a, b) -> b
snd ParamSet NExpr
pset)
      (Set VarName -> Set VarName -> Set VarName
forall a. Ord a => Set a -> Set a -> Set a
Set.difference
        (VarName -> Set VarName
forall x. One x => OneItem x -> x
one (VarName -> Set VarName) -> Maybe VarName -> Set VarName
forall b a. Monoid b => (a -> b) -> Maybe a -> b
`whenJust` Maybe VarName
varname)
        ([VarName] -> Set VarName
forall a. Ord a => [a] -> Set a
Set.fromList ([VarName] -> Set VarName) -> [VarName] -> Set VarName
forall a b. (a -> b) -> a -> b
$ (VarName, Maybe NExpr) -> VarName
forall a b. (a, b) -> a
fst ((VarName, Maybe NExpr) -> VarName) -> ParamSet NExpr -> [VarName]
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> ParamSet NExpr
pset)
      )
  (NLet         [Binding NExpr]
bindings NExpr
expr   ) ->
    NExpr -> Set VarName
freeVars NExpr
expr Set VarName -> Set VarName -> Set VarName
forall a. Semigroup a => a -> a -> a
<>
    ([Binding NExpr] -> Set VarName)
-> ([Binding NExpr] -> Set VarName)
-> [Binding NExpr]
-> Set VarName
forall a.
(a -> Set VarName) -> (a -> Set VarName) -> a -> Set VarName
diffBetween [Binding NExpr] -> Set VarName
forall (t :: * -> *).
Foldable t =>
t (Binding NExpr) -> Set VarName
bindFreeVars [Binding NExpr] -> Set VarName
forall (t :: * -> *).
Foldable t =>
t (Binding NExpr) -> Set VarName
bindDefs [Binding NExpr]
bindings
  (NIf          NExpr
cond NExpr
th   NExpr
el    ) -> [Set VarName] -> Set VarName
forall (f :: * -> *) a. (Foldable f, Ord a) => f (Set a) -> Set a
Set.unions ([Set VarName] -> Set VarName) -> [Set VarName] -> Set VarName
forall a b. (a -> b) -> a -> b
$ NExpr -> Set VarName
freeVars (NExpr -> Set VarName) -> [NExpr] -> [Set VarName]
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> [NExpr
cond, NExpr
th, NExpr
el]
  -- Evaluation is needed to find out whether x is a "real" free variable in `with y; x`, we just include it
  -- This also makes sense because its value can be overridden by `x: with y; x`
  (NWith        NExpr
set  NExpr
expr       ) -> NExpr -> NExpr -> Set VarName
collectFreeVars NExpr
set NExpr
expr
  (NAssert      NExpr
assertion NExpr
expr  ) -> NExpr -> NExpr -> Set VarName
collectFreeVars NExpr
assertion NExpr
expr
  (NSynHole     VarName
_               ) -> Set VarName
forall a. Monoid a => a
mempty

 where

  diffBetween :: (a -> Set VarName) -> (a -> Set VarName) -> a -> Set VarName
  diffBetween :: forall a.
(a -> Set VarName) -> (a -> Set VarName) -> a -> Set VarName
diffBetween a -> Set VarName
g a -> Set VarName
f a
b = Set VarName -> Set VarName -> Set VarName
forall a. Ord a => Set a -> Set a -> Set a
Set.difference (a -> Set VarName
g a
b) (a -> Set VarName
f a
b)

  collectFreeVars :: NExpr -> NExpr -> Set VarName
  collectFreeVars :: NExpr -> NExpr -> Set VarName
collectFreeVars = Set VarName -> Set VarName -> Set VarName
forall a. Semigroup a => a -> a -> a
(<>) (Set VarName -> Set VarName -> Set VarName)
-> (NExpr -> Set VarName) -> NExpr -> NExpr -> Set VarName
forall b c a. (b -> b -> c) -> (a -> b) -> a -> a -> c
`on` NExpr -> Set VarName
freeVars

  bindDefs :: Foldable t => t (Binding NExpr) -> Set VarName
  bindDefs :: forall (t :: * -> *).
Foldable t =>
t (Binding NExpr) -> Set VarName
bindDefs = (Binding NExpr -> Set VarName) -> t (Binding NExpr) -> Set VarName
forall (t :: * -> *) m a.
(Foldable t, Monoid m) =>
(a -> m) -> t a -> m
foldMap Binding NExpr -> Set VarName
forall r. Binding r -> Set VarName
bind1Def
   where
    bind1Def :: Binding r -> Set VarName
    bind1Def :: forall r. Binding r -> Set VarName
bind1Def (Inherit   Maybe r
Nothing                  [VarName]
_    SourcePos
_) = Set VarName
forall a. Monoid a => a
mempty
    bind1Def (Inherit  (Just r
_                 ) [VarName]
keys SourcePos
_) = [VarName] -> Set VarName
forall a. Ord a => [a] -> Set a
Set.fromList [VarName]
keys
    bind1Def (NamedVar (StaticKey  VarName
varname :| [NKeyName r]
_) r
_    SourcePos
_) = OneItem (Set VarName) -> Set VarName
forall x. One x => OneItem x -> x
one OneItem (Set VarName)
VarName
varname
    bind1Def (NamedVar (DynamicKey Antiquoted (NString r) r
_       :| [NKeyName r]
_) r
_    SourcePos
_) = Set VarName
forall a. Monoid a => a
mempty

  bindFreeVars :: Foldable t => t (Binding NExpr) -> Set VarName
  bindFreeVars :: forall (t :: * -> *).
Foldable t =>
t (Binding NExpr) -> Set VarName
bindFreeVars = (Binding NExpr -> Set VarName) -> t (Binding NExpr) -> Set VarName
forall (t :: * -> *) m a.
(Foldable t, Monoid m) =>
(a -> m) -> t a -> m
foldMap Binding NExpr -> Set VarName
bind1Free
   where
    bind1Free :: Binding NExpr -> Set VarName
    bind1Free :: Binding NExpr -> Set VarName
bind1Free (Inherit  Maybe NExpr
Nothing     [VarName]
keys SourcePos
_) = [VarName] -> Set VarName
forall a. Ord a => [a] -> Set a
Set.fromList [VarName]
keys
    bind1Free (Inherit (Just NExpr
scope) [VarName]
_    SourcePos
_) = NExpr -> Set VarName
freeVars NExpr
scope
    bind1Free (NamedVar NAttrPath NExpr
path        NExpr
expr SourcePos
_) = NAttrPath NExpr -> Set VarName
pathFree NAttrPath NExpr
path Set VarName -> Set VarName -> Set VarName
forall a. Semigroup a => a -> a -> a
<> NExpr -> Set VarName
freeVars NExpr
expr

  pathFree :: NAttrPath NExpr -> Set VarName
  pathFree :: NAttrPath NExpr -> Set VarName
pathFree = (NKeyName NExpr -> Set VarName) -> NAttrPath NExpr -> Set VarName
forall (t :: * -> *) m a.
(Foldable t, Monoid m) =>
(a -> m) -> t a -> m
foldMap NKeyName NExpr -> Set VarName
forall (t :: * -> *). Foldable t => t NExpr -> Set VarName
mapFreeVars

  mapFreeVars :: Foldable t => t NExpr -> Set VarName
  mapFreeVars :: forall (t :: * -> *). Foldable t => t NExpr -> Set VarName
mapFreeVars = (NExpr -> Set VarName) -> t NExpr -> Set VarName
forall (t :: * -> *) m a.
(Foldable t, Monoid m) =>
(a -> m) -> t a -> m
foldMap NExpr -> Set VarName
freeVars


class ToExpr a where
  toExpr :: a -> NExprLoc

instance ToExpr NExprLoc where
  toExpr :: NExprLoc -> NExprLoc
toExpr = NExprLoc -> NExprLoc
forall a. a -> a
id

instance ToExpr VarName where
  toExpr :: VarName -> NExprLoc
toExpr = SrcSpan -> VarName -> NExprLoc
NSymAnn SrcSpan
nullSpan

instance ToExpr Int where
  toExpr :: Int -> NExprLoc
toExpr = SrcSpan -> NAtom -> NExprLoc
NConstantAnn SrcSpan
nullSpan (NAtom -> NExprLoc) -> (Int -> NAtom) -> Int -> NExprLoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Integer -> NAtom
NInt (Integer -> NAtom) -> (Int -> Integer) -> Int -> NAtom
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> Integer
forall a b. (Integral a, Num b) => a -> b
fromIntegral

instance ToExpr Integer where
  toExpr :: Integer -> NExprLoc
toExpr = SrcSpan -> NAtom -> NExprLoc
NConstantAnn SrcSpan
nullSpan (NAtom -> NExprLoc) -> (Integer -> NAtom) -> Integer -> NExprLoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Integer -> NAtom
NInt

instance ToExpr Float where
  toExpr :: Float -> NExprLoc
toExpr = SrcSpan -> NAtom -> NExprLoc
NConstantAnn SrcSpan
nullSpan (NAtom -> NExprLoc) -> (Float -> NAtom) -> Float -> NExprLoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Float -> NAtom
NFloat

metaExp :: Set VarName -> NExprLoc -> Maybe ExpQ
metaExp :: Set VarName -> NExprLoc -> Maybe ExpQ
metaExp Set VarName
fvs (NSymAnn SrcSpan
_ VarName
x) | VarName
x VarName -> Set VarName -> Bool
forall a. Ord a => a -> Set a -> Bool
`Set.member` Set VarName
fvs =
  ExpQ -> Maybe ExpQ
forall (f :: * -> *) a. Applicative f => a -> f a
pure [| toExpr $(varE (mkName $ toString x)) |]
metaExp Set VarName
_ NExprLoc
_ = Maybe ExpQ
forall a. Maybe a
Nothing

metaPat :: Set VarName -> NExprLoc -> Maybe PatQ
metaPat :: Set VarName -> NExprLoc -> Maybe PatQ
metaPat Set VarName
fvs (NSymAnn SrcSpan
_ VarName
x) | VarName
x VarName -> Set VarName -> Bool
forall a. Ord a => a -> Set a -> Bool
`Set.member` Set VarName
fvs =
  PatQ -> Maybe PatQ
forall (f :: * -> *) a. Applicative f => a -> f a
pure (PatQ -> Maybe PatQ) -> PatQ -> Maybe PatQ
forall a b. (a -> b) -> a -> b
$ Name -> PatQ
forall (m :: * -> *). Quote m => Name -> m Pat
varP (Name -> PatQ) -> Name -> PatQ
forall a b. (a -> b) -> a -> b
$ String -> Name
mkName (String -> Name) -> String -> Name
forall a b. (a -> b) -> a -> b
$ VarName -> String
forall a. ToString a => a -> String
toString VarName
x
metaPat Set VarName
_ NExprLoc
_ = Maybe PatQ
forall a. Maybe a
Nothing

-- Use of @QuasiQuoter@ requires @String@.
-- After @Text -> String@ migrations done, _maybe_ think to use @QuasiText@.
nix :: QuasiQuoter
nix :: QuasiQuoter
nix = QuasiQuoter :: (String -> ExpQ)
-> (String -> PatQ)
-> (String -> Q Type)
-> (String -> Q [Dec])
-> QuasiQuoter
QuasiQuoter { quoteExp :: String -> ExpQ
quoteExp = String -> ExpQ
quoteExprExp, quotePat :: String -> PatQ
quotePat = String -> PatQ
quoteExprPat }