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Create data types to avoid coerceToString boolean blindness

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This commit is contained in:
Doug Beardsley 2018-11-17 18:26:10 -05:00
parent 5fb9dae34c
commit 4edcda00e4
2 changed files with 29 additions and 14 deletions
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2
src/Nix/Builtins.hs
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@ -324,7 +324,7 @@ nixPath = fmap nvList $ flip foldNixPath [] $ \p mn ty rest ->
nvStr (hackyMakeNixStringWithoutContext $ Text.pack (fromMaybe "" mn))) ]) : rest
toString :: MonadNix e m => m (NValue m) -> m (NValue m)
toString str = str >>= coerceToString False True >>= toNix
toString str = str >>= coerceToString DontCopyToStore CoerceAny >>= toNix
hasAttr :: forall e m. MonadNix e m => m (NValue m) -> m (NValue m) -> m (NValue m)
hasAttr x y =

41
src/Nix/Exec.hs
View file

@ -375,14 +375,14 @@ execBinaryOp scope span op lval rarg = do
(ls@NVSet {}, NVStr rs) -> case op of
NPlus -> (\ls2 -> bin nvStrP (ls2 `principledStringMappend` rs))
<$> coerceToString False False ls
<$> coerceToString DontCopyToStore CoerceStringy ls
NEq -> toBool =<< valueEq lval rval
NNEq -> toBool . not =<< valueEq lval rval
_ -> nverr $ ErrorCall $ unsupportedTypes lval rval
(NVStr ls, rs@NVSet {}) -> case op of
NPlus -> (\rs2 -> bin nvStrP (ls `principledStringMappend` rs2))
<$> coerceToString False False rs
<$> coerceToString DontCopyToStore CoerceStringy rs
NEq -> toBool =<< valueEq lval rval
NNEq -> toBool . not =<< valueEq lval rval
_ -> nverr $ ErrorCall $ unsupportedTypes lval rval
@ -443,22 +443,37 @@ execBinaryOp scope span op lval rarg = do
toInt = pure . bin nvConstantP . NInt
toFloat = pure . bin nvConstantP . NFloat
-- coerceNix = toNix . Text.pack <=< coerceToString True True
coerceToString :: MonadNix e m => Bool -> Bool -> NValue m -> m NixString
coerceToString copyToStore coerceMore = go
-- | Data type to avoid boolean blindness on what used to be called coerceMore
data CoercionLevel
= CoerceStringy
-- ^ Coerce only stringlike types: strings, paths, and appropriate sets
| CoerceAny
-- ^ Coerce everything but functions
deriving (Eq,Ord,Enum,Bounded)
-- | Data type to avoid boolean blindness on what used to be called copyToStore
data CopyToStoreMode
= CopyToStore
-- ^ Add paths to the store as they are encountered
| DontCopyToStore
-- ^ Add paths to the store as they are encountered
deriving (Eq,Ord,Enum,Bounded)
coerceToString :: MonadNix e m => CopyToStoreMode -> CoercionLevel -> NValue m -> m NixString
coerceToString ctsm clevel = go
where
go = \case
NVConstant (NBool b)
-- TODO Return a singleton for "" and "1"
| b && coerceMore -> pure $ principledMakeNixStringWithoutContext "1"
| coerceMore -> pure $ principledMakeNixStringWithoutContext ""
NVConstant (NInt n) | coerceMore -> pure $ principledMakeNixStringWithoutContext $ Text.pack $ show n
NVConstant (NFloat n) | coerceMore -> pure $ principledMakeNixStringWithoutContext $ Text.pack $ show n
NVConstant NNull | coerceMore -> pure $ principledMakeNixStringWithoutContext ""
| b && clevel == CoerceAny -> pure $ principledMakeNixStringWithoutContext "1"
| clevel == CoerceAny -> pure $ principledMakeNixStringWithoutContext ""
NVConstant (NInt n) | clevel == CoerceAny -> pure $ principledMakeNixStringWithoutContext $ Text.pack $ show n
NVConstant (NFloat n) | clevel == CoerceAny -> pure $ principledMakeNixStringWithoutContext $ Text.pack $ show n
NVConstant NNull | clevel == CoerceAny -> pure $ principledMakeNixStringWithoutContext ""
NVStr ns -> pure ns
NVPath p | copyToStore -> storePathToNixString <$> addPath p
NVPath p | ctsm == CopyToStore -> storePathToNixString <$> addPath p
| otherwise -> pure $ principledMakeNixStringWithoutContext $ Text.pack p
NVList l | coerceMore -> nixStringUnwords <$> traverse (`force` go) l
NVList l | clevel == CoerceAny -> nixStringUnwords <$> traverse (`force` go) l
v@(NVSet s _) | Just p <- M.lookup "__toString" s ->
force p $ (`callFunc` pure v) >=> go
@ -604,7 +619,7 @@ instance (MonadFix m, MonadCatch m, MonadIO m, Alternative m,
NVConstant NNull | ignoreNulls -> pure Nothing
v' -> Just <$> coerceNix v'
where
coerceNix = toNix <=< coerceToString True True
coerceNix = toNix <=< coerceToString CopyToStore CoerceAny
nixInstantiateExpr expr = do
traceM $ "Executing: "