15bf5b34d4
As a result, `NVBuiltin2` is not needed any more, and `NVBuiltin1` gets renamed to `NVBuiltin`
98 lines
3.4 KiB
Haskell
98 lines
3.4 KiB
Haskell
|
|
module Nix.Builtins (baseEnv, builtins, evalTopLevelExpr) where
|
|
|
|
import Control.Applicative
|
|
import Control.Monad hiding (mapM, sequence)
|
|
import Control.Monad.Fix
|
|
import Data.Fix
|
|
import qualified Data.Map as Map
|
|
import Data.Text (Text)
|
|
import qualified Data.Text as Text
|
|
import Data.Traversable (mapM)
|
|
import Nix.Atoms
|
|
import Nix.Eval
|
|
import Nix.Expr (NExpr)
|
|
import Prelude hiding (mapM, sequence)
|
|
|
|
-- | Evaluate a nix expression in the default context
|
|
evalTopLevelExpr :: MonadFix m => NExpr -> m (NValue m)
|
|
evalTopLevelExpr val = evalExpr val baseEnv
|
|
|
|
baseEnv :: MonadFix m => ValueSet m
|
|
baseEnv = Map.fromList $ [ ("builtins", Fix $ NVSet builtins) ] ++ topLevelBuiltins
|
|
where
|
|
topLevelBuiltins = map mapping $ filter isTopLevel builtinsList
|
|
-- builtins = Map.fromList $ map mapping $ builtinsList
|
|
|
|
builtins :: MonadFix m => ValueSet m
|
|
builtins = Map.fromList $ map mapping $ builtinsList
|
|
|
|
data BuiltinType = Normal | TopLevel
|
|
data Builtin m = Builtin {kind :: BuiltinType, mapping :: (Text, NValue m) }
|
|
|
|
isTopLevel :: Builtin m -> Bool
|
|
isTopLevel b = case kind b of
|
|
Normal -> False
|
|
TopLevel -> True
|
|
|
|
builtinsList :: MonadFix m => [ Builtin m ]
|
|
builtinsList = [
|
|
topLevel ("toString", prim_toString)
|
|
, basic ("hasAttr" , prim_hasAttr)
|
|
, basic ("getAttr" , prim_getAttr)
|
|
, basic ("any" , prim_any )
|
|
, basic ("all" , prim_all )
|
|
]
|
|
where
|
|
basic = Builtin Normal
|
|
topLevel = Builtin TopLevel
|
|
|
|
|
|
-- Helpers
|
|
|
|
mkBool :: Bool -> NValue m
|
|
mkBool = Fix . NVConstant . NBool
|
|
|
|
extractBool :: NValue m -> Bool
|
|
extractBool (Fix (NVConstant (NBool b))) = b
|
|
extractBool _ = error "Not a bool constant"
|
|
|
|
evalPred :: NValue m -> NValue m -> m (NValue m)
|
|
evalPred (Fix (NVFunction argset pred)) = pred . buildArgument argset
|
|
evalPred pred = error $ "Trying to call a " ++ show pred
|
|
|
|
|
|
-- Primops
|
|
|
|
prim_toString :: MonadFix m => Functor m => NValue m
|
|
prim_toString = builtin "toString" $ toString
|
|
toString :: MonadFix m => NValue m -> m (NValue m)
|
|
toString s = return $ Fix $ uncurry NVStr $ valueText s
|
|
|
|
prim_hasAttr :: MonadFix m => NValue m
|
|
prim_hasAttr = builtin2 "hasAttr" hasAttr
|
|
hasAttr :: MonadFix m => NValue m -> NValue m -> m (NValue m)
|
|
hasAttr (Fix (NVStr key _)) (Fix (NVSet aset)) = return $ Fix $ NVConstant $ NBool $ Map.member key aset
|
|
hasAttr key aset = error $ "Invalid types for builtin.hasAttr: " ++ show (key, aset)
|
|
|
|
prim_getAttr :: MonadFix m => NValue m
|
|
prim_getAttr = builtin2 "getAttr" getAttr
|
|
getAttr :: MonadFix m => NValue m -> NValue m -> m (NValue m)
|
|
getAttr (Fix (NVStr key _)) (Fix (NVSet aset)) = return $ Map.findWithDefault _err key aset
|
|
where _err = error ("Field does not exist " ++ Text.unpack key)
|
|
getAttr key aset = error $ "Invalid types for builtin.getAttr: " ++ show (key, aset)
|
|
|
|
|
|
prim_any :: MonadFix m => NValue m
|
|
prim_any = builtin2 "any" _any
|
|
_any :: MonadFix m => NValue m -> NValue m -> m (NValue m)
|
|
_any pred (Fix (NVList l)) = mkBool . any extractBool <$> mapM (evalPred pred) l
|
|
_any _ list = error $ "builtins.any takes a list as second argument, not a " ++ show list
|
|
|
|
prim_all :: MonadFix m => NValue m
|
|
prim_all = builtin2 "all" _all
|
|
_all :: MonadFix m => NValue m -> NValue m -> m (NValue m)
|
|
_all pred (Fix (NVList l)) = mkBool . all extractBool <$> mapM (evalPred pred) l
|
|
_all _ list = error $ "builtins.all takes a list as second argument, not a " ++ show list
|
|
|