String: unflip StringContext

Author: Anton-Latukha

src/Nix/Builtins.hs

@@ -1139,7 +1139,7 @@ toFileNix name s =
 
     let
       storepath  = coerce (fromString @Text) mres
-      sc = StringContext storepath DirectPath
+      sc = StringContext DirectPath storepath
 
     toValue $ mkNixStringWithSingletonContext storepath sc
 

src/Nix/Convert.hs

@@ -218,7 +218,7 @@ instance ( Convertible e t f m
     \case
       NVStr' ns -> pure $ pure ns
       NVPath' p ->
-        (\path -> pure $ (`mkNixStringWithSingletonContext` (`StringContext` DirectPath) path) path ) . fromString . coerce <$>
+        (\path -> pure $ (`mkNixStringWithSingletonContext` StringContext DirectPath path) path ) . fromString . coerce <$>
           addPath p
       NVSet' _ s ->
         maybe

src/Nix/Effects/Derivation.hs

@@ -289,9 +289,9 @@ defaultDerivationStrict val = do
     let
       outputsWithContext =
         Map.mapWithKey
-          (\out (coerce -> path) -> mkNixStringWithSingletonContext path $ StringContext drvPath $ DerivationOutput out)
+          (\out (coerce -> path) -> mkNixStringWithSingletonContext path $ StringContext (DerivationOutput out) drvPath)
           (outputs drv')
-      drvPathWithContext = mkNixStringWithSingletonContext drvPath $ StringContext drvPath AllOutputs
+      drvPathWithContext = mkNixStringWithSingletonContext drvPath $ StringContext AllOutputs drvPath 
       attrSet = mkNVStr <$> M.fromList (("drvPath", drvPathWithContext) : Map.toList outputsWithContext)
     -- TODO: Add location information for all the entries.
     --              here --v
@@ -309,13 +309,14 @@ defaultDerivationStrict val = do
     toStorePaths = foldl (flip addToInputs) mempty
 
     addToInputs :: Bifunctor p => StringContext -> p (Set Text) (Map Text [Text])  -> p (Set Text) (Map Text [Text])
-    addToInputs (StringContext (coerce -> path) kind) = case kind of
-      DirectPath -> first $ Set.insert path
-      DerivationOutput o -> second $ Map.insertWith (<>) path $ one o
-      AllOutputs ->
-        -- TODO: recursive lookup. See prim_derivationStrict
-        -- XXX: When is this really used ?
-        error "Not implemented: derivations depending on a .drv file are not yet supported."
+    addToInputs (StringContext kind (coerce -> path)) =
+      case kind of
+        DirectPath -> first $ Set.insert path
+        DerivationOutput o -> second $ Map.insertWith (<>) path $ one o
+        AllOutputs ->
+          -- TODO: recursive lookup. See prim_derivationStrict
+          -- XXX: When is this really used ?
+          error "Not implemented: derivations depending on a .drv file are not yet supported."
 
 
 -- | Build a derivation in a context collecting string contexts.

src/Nix/Json.hs

@@ -72,7 +72,7 @@ toJSON = \case
   NVPath p ->
     do
       fp <- lift $ coerce <$> addPath p
-      addSingletonStringContext $ StringContext (fromString fp) DirectPath
+      addSingletonStringContext $ StringContext DirectPath $ fromString fp
       pure $ A.toJSON fp
   v -> lift $ throwError $ CoercionToJson v
 

src/Nix/String.hs

@@ -45,12 +45,11 @@ import           Nix.Expr.Types                 ( VarName(..)
 
 -- ** Context
 
---  2021-07-18: NOTE: it should be ContextFlavor -> Varname.
 -- | A Nix 'StringContext' ...
 data StringContext =
   StringContext
-    { scPath :: !VarName
-    , scFlavor :: !ContextFlavor
+    { scFlavor :: !ContextFlavor
+    , scPath :: !VarName
     }
   deriving (Eq, Ord, Show, Generic)
 
@@ -153,7 +152,7 @@ getContext = nsContext
 
 fromNixLikeContext :: NixLikeContext -> S.HashSet StringContext
 fromNixLikeContext =
-  S.fromList . (toStringContexts <=< (M.toList . getNixLikeContext))
+  S.fromList . (uncurry toStringContexts <=< M.toList . getNixLikeContext)
 
 -- | Extract the string contents from a NixString that has no context
 getStringNoContext :: NixString -> Maybe Text
@@ -176,9 +175,8 @@ extractNixString (NixString s c) =
 
 -- this really should be 2 args, then with @toStringContexts path@ laziness it would tail recurse.
 -- for now tuple dissected internaly with laziness preservation.
-toStringContexts :: (VarName, NixLikeContextValue) -> [StringContext]
-toStringContexts ~(path, nlcv) =
-  go nlcv
+toStringContexts :: VarName -> NixLikeContextValue -> [StringContext]
+toStringContexts path = go
  where
   go :: NixLikeContextValue -> [StringContext]
   go cv =
@@ -192,10 +190,10 @@ toStringContexts ~(path, nlcv) =
       _ -> mempty
    where
     mkCtxFor :: ContextFlavor -> StringContext
-    mkCtxFor = StringContext path
-
+    mkCtxFor context = StringContext context path
     mkLstCtxFor :: ContextFlavor -> NixLikeContextValue -> [StringContext]
-    mkLstCtxFor t c = mkCtxFor t : go c
+    mkLstCtxFor t c = one (mkCtxFor t) <> go c
+
 
 toNixLikeContextValue :: StringContext -> (VarName, NixLikeContextValue)
 toNixLikeContextValue sc =

src/Nix/String/Coerce.hs

@@ -134,4 +134,4 @@ coercePathToNixString =
  where
   storePathToNixString :: StorePath -> NixString
   storePathToNixString =
-    (mkNixStringWithSingletonContext <*> (`StringContext` DirectPath)) . fromString . coerce
+    (mkNixStringWithSingletonContext <*> StringContext DirectPath) . fromString . coerce