Add F version to shorthands

Nix/Expr/Shorthands.hs

@@ -1,4 +1,7 @@
 -- | A bunch of shorthands for making nix expressions.
+--
+-- Functions with an @F@ suffix return a more general type without the outer
+-- 'Fix' wrapper.
 module Nix.Expr.Shorthands where
 
 import Prelude
@@ -10,8 +13,11 @@ import Nix.Atoms
 import Nix.Expr.Types
 
 -- | Make an integer literal expression.
-mkInt :: Integer -> NExprF a
-mkInt = NConstant . NInt
+mkInt :: Integer -> NExpr
+mkInt = Fix . mkIntF
+
+mkIntF :: Integer -> NExprF a
+mkIntF = NConstant . NInt
 
 -- | Make a regular (double-quoted) string.
 mkStr :: Text -> NExpr
@@ -26,35 +32,56 @@ mkIndentedStr = Fix . NStr . Indented . \case
   x -> [Plain x]
 
 -- | Make a literal URI expression.
-mkUri :: Text -> NExprF a
-mkUri = NConstant . NUri
+mkUri :: Text -> NExpr
+mkUri = Fix . mkUriF
+
+mkUriF :: Text -> NExprF a
+mkUriF = NConstant . NUri
 
 -- | Make a path. Use 'True' if the path should be read from the
 -- environment, else 'False'.
-mkPath :: Bool -> FilePath -> NExprF a
-mkPath False = NLiteralPath
-mkPath True = NEnvPath
+mkPath :: Bool -> FilePath -> NExpr
+mkPath b = Fix . mkPathF b
+
+mkPathF :: Bool -> FilePath -> NExprF a
+mkPathF False = NLiteralPath
+mkPathF True = NEnvPath
 
 -- | Make a path expression which pulls from the NIX_PATH env variable.
-mkEnvPath :: FilePath -> NExprF a
-mkEnvPath = mkPath True
+mkEnvPath :: FilePath -> NExpr
+mkEnvPath = Fix . mkEnvPathF
+
+mkEnvPathF :: FilePath -> NExprF a
+mkEnvPathF = mkPathF True
 
 -- | Make a path expression which references a relative path.
-mkRelPath :: FilePath -> NExprF a
-mkRelPath = mkPath False
+mkRelPath :: FilePath -> NExpr
+mkRelPath = Fix . mkRelPathF
+
+mkRelPathF :: FilePath -> NExprF a
+mkRelPathF = mkPathF False
 
 -- | Make a variable (symbol)
-mkSym :: Text -> NExprF a
-mkSym = NSym
+mkSym :: Text -> NExpr
+mkSym = Fix . mkSymF
+
+mkSymF :: Text -> NExprF a
+mkSymF = NSym
 
 mkSelector :: Text -> NAttrPath NExpr
 mkSelector = (:[]) . StaticKey
 
-mkBool :: Bool -> NExprF a
-mkBool = NConstant . NBool
+mkBool :: Bool -> NExpr
+mkBool = Fix . mkBoolF
 
-mkNull :: NExprF a
-mkNull = NConstant NNull
+mkBoolF :: Bool -> NExprF a
+mkBoolF = NConstant . NBool
+
+mkNull :: NExpr
+mkNull = Fix mkNullF
+
+mkNullF :: NExprF a
+mkNullF = NConstant NNull
 
 mkOper :: NUnaryOp -> NExpr -> NExpr
 mkOper op = Fix . NUnary op

Nix/Parser.hs

@@ -99,18 +99,18 @@ nixToplevelForm :: Parser NExprLoc
 nixToplevelForm = choice [nixLambda, nixLet, nixIf, nixAssert, nixWith]
 
 nixSym :: Parser NExprLoc
-nixSym = annotateLocation1 $ mkSym <$> identifier
+nixSym = annotateLocation1 $ mkSymF <$> identifier
 
 nixInt :: Parser NExprLoc
-nixInt = annotateLocation1 $ mkInt <$> token decimal <?> "integer"
+nixInt = annotateLocation1 $ mkIntF <$> token decimal <?> "integer"
 
 nixBool :: Parser NExprLoc
 nixBool = annotateLocation1 $ try (true <|> false) <?> "bool" where
-  true = mkBool True <$ symbol "true"
-  false = mkBool False <$ symbol "false"
+  true = mkBoolF True <$ symbol "true"
+  false = mkBoolF False <$ symbol "false"
 
 nixNull :: Parser NExprLoc
-nixNull = annotateLocation1 $ mkNull <$ try (symbol "null") <?> "null"
+nixNull = annotateLocation1 $ mkNullF <$ try (symbol "null") <?> "null"
 
 nixParens :: Parser NExprLoc
 nixParens = parens nixExprLoc <?> "parens"
@@ -127,11 +127,11 @@ slash = try (char '/' <* notFollowedBy (char '/')) <?> "slash"
 -- | A path surrounded by angle brackets, indicating that it should be
 -- looked up in the NIX_PATH environment variable at evaluation.
 nixSPath :: Parser NExprLoc
-nixSPath = annotateLocation1 $ mkPath True <$> try (char '<' *> some (oneOf pathChars <|> slash) <* symbolic '>')
+nixSPath = annotateLocation1 $ mkPathF True <$> try (char '<' *> some (oneOf pathChars <|> slash) <* symbolic '>')
         <?> "spath"
 
 nixPath :: Parser NExprLoc
-nixPath = annotateLocation1 $ token $ fmap (mkPath False) $ ((++)
+nixPath = annotateLocation1 $ token $ fmap (mkPathF False) $ ((++)
     <$> (try ((++) <$> many (oneOf pathChars) <*> fmap (:[]) slash) <?> "path")
     <*> fmap concat
       (  some (some (oneOf pathChars)
@@ -173,7 +173,7 @@ uriAfterColonC :: Parser Char
 uriAfterColonC = alphaNum <|> oneOf "%/?:@&=+$,-_.!~*'"
 
 nixUri :: Parser NExprLoc
-nixUri = annotateLocation1 $ token $ fmap (mkUri . pack) $ (++)
+nixUri = annotateLocation1 $ token $ fmap (mkUriF . pack) $ (++)
   <$> try ((++) <$> (scheme <* char ':') <*> fmap (\x -> [':',x]) uriAfterColonC)
   <*> many uriAfterColonC
  where