From 0f0f865e4f03cd85e8068a337459cb9aa2c7b4a5 Mon Sep 17 00:00:00 2001
From: John Wiegley <johnw@newartisans.com>
Date: Fri, 4 Jul 2014 16:15:58 -0500
Subject: [PATCH] Add a reserved words as "stop words" for nixApp

---
 Nix/Parser.hs         | 10 +++++-----
 Nix/Parser/Library.hs | 33 ++++++++++++++++++++-------------
 2 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/Nix/Parser.hs b/Nix/Parser.hs
index 1024b7a..8e737a3 100644
--- a/Nix/Parser.hs
+++ b/Nix/Parser.hs
@@ -22,7 +22,7 @@ nixApp = go <$> someTill (whiteSpace *> nixExpr True) (try (lookAhead stop))
     go [x]    = x
     go (f:xs) = Fix (NApp f (go xs))
 
-    stop = () <$ oneOf "=,;])}" <|> eof
+    stop = () <$ oneOf "=,;])}" <|> reservedWords <|> eof
 
 nixExpr :: Bool -> Parser NExpr
 nixExpr = buildExpressionParser table . nixTerm
@@ -81,13 +81,13 @@ nixPath :: Parser NExpr
 nixPath = try $ fmap mkPath $ mfilter ('/' `elem`) $ some (oneOf "A-Za-z_0-9.:/")
 
 nixLet :: Parser NExpr
-nixLet =  (Fix .) . NLet
+nixLet =  fmap Fix $ NLet
       <$> (reserved "let" *> nixBinders)
       <*> (whiteSpace *> reserved "in" *> nixApp)
 
 nixIf :: Parser NExpr
-nixIf =  ((Fix .) .) . NIf
-     <$> (reserved "if" *> nixExpr False)
+nixIf =  fmap Fix $ NIf
+     <$> (reserved "if" *> nixApp)
      <*> (whiteSpace *> reserved "then" *> nixApp)
      <*> (whiteSpace *> reserved "else" *> nixApp)
 
@@ -159,7 +159,7 @@ setOrArgs = do
             trace "parsing arguments" $ return ()
             args <- argExpr <?> "arguments"
             trace ("args: " ++ show args) $ return ()
-            symbolic ':' *> ((Fix .) . NAbs <$> pure args <*> nixApp)
+            symbolic ':' *> fmap Fix (NAbs <$> pure args <*> nixApp)
                 <|> pure args
 
 lookaheadForSet :: Parser Bool
diff --git a/Nix/Parser/Library.hs b/Nix/Parser/Library.hs
index 583b5b3..0d36bf9 100644
--- a/Nix/Parser/Library.hs
+++ b/Nix/Parser/Library.hs
@@ -3,12 +3,13 @@
 module Nix.Parser.Library ( module Nix.Parser.Library, module X ) where
 
 import           Control.Applicative
+import           Data.Foldable
 
 #if USE_PARSEC
 
 import           Control.Monad
 import           Control.Monad.IO.Class
-import           Data.Text as T
+import           Data.Text as T hiding (map)
 import           Data.Text.IO as T
 import           Text.Parsec as X hiding ((<|>), many, optional)
 import           Text.Parsec.Expr as X
@@ -26,17 +27,7 @@ lexer = P.makeTokenParser P.LanguageDef
     , P.identLetter     = alphaNum <|> oneOf "_"
     , P.opStart         = oneOf ":!#$%&*+./<=>?@\\^|-~"
     , P.opLetter        = oneOf "@"
-    , P.reservedNames   =
-        [ "let", "in"
-        , "if", "then", "else"
-        , "true", "false"
-        , "null"
-        , "assert"
-        , "with"
-        , "rec"
-        , "inherit"
-        , "or"
-        ]
+    , P.reservedNames   = reservedNames
     , P.reservedOpNames = []
     , P.caseSensitive   = True
     }
@@ -77,7 +68,7 @@ parseFromFileEx p path =
 
 import Data.Char
 import Data.List (nub)
-import Data.Text
+import Data.Text hiding (map)
 import Text.Parser.Expression as X
 import Text.Parser.LookAhead as X
 import Text.Trifecta as X hiding (whiteSpace, symbol, symbolic)
@@ -143,6 +134,22 @@ inCommentSingle
 
 #endif
 
+reservedNames :: [String]
+reservedNames =
+    [ "let", "in"
+    , "if", "then", "else"
+    , "true", "false"
+    , "null"
+    , "assert"
+    , "with"
+    , "rec"
+    , "inherit"
+    , "or"
+    ]
+
+reservedWords :: Parser ()
+reservedWords = () <$ asum (map string reservedNames)
+
 someTill :: Parser a -> Parser end -> Parser [a]
 someTill p end = go
   where