From 24a4ffdce4b580ba6a0fed1c86419700a610ba46 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Benno=20F=C3=BCnfst=C3=BCck?= <benno.fuenfstueck@gmail.com>
Date: Sat, 16 Aug 2014 01:17:01 +0200
Subject: [PATCH] now really fix parsing paths

---
 Nix/Parser.hs        | 24 ++++++++++--------------
 tests/ParserTests.hs |  7 +++++--
 2 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/Nix/Parser.hs b/Nix/Parser.hs
index 7516881..ae0b8e8 100644
--- a/Nix/Parser.hs
+++ b/Nix/Parser.hs
@@ -43,20 +43,19 @@ nixAntiquoted :: Parser a -> Parser (Antiquoted a NExpr)
 nixAntiquoted p = Plain <$> p
  <|> Antiquoted <$> (try (string "${") *> whiteSpace *> nixApp <* symbolic '}')
 
+selDot :: Parser ()
+selDot = try (char '.' *> notFollowedBy (("path" :: String) <$ nixPath)) *> whiteSpace
+
 nixSelector :: Parser (NSelector NExpr)
-nixSelector = keyName `sepBy1` symbolic '.'
+nixSelector = keyName `sepBy1` selDot where
 
 nixSelect :: Parser NExpr -> Parser NExpr
 nixSelect term = build
   <$> term
-  <*> optional (char '.' *> choice
-    [ Left <$> nixPath
-    , fmap Right $ (,) <$> nixSelector <*> optional (reserved "or" *> nixApp)
-    ])
+  <*> optional ((,) <$> (selDot *> nixSelector) <*> optional (reserved "or" *> nixApp))
  where
   build t Nothing = t
-  build t (Just (Left p)) = Fix $ NApp t (mkPath $ '.' : p)
-  build t (Just (Right (s,o))) = Fix $ NSelect t s o
+  build t (Just (s,o)) = Fix $ NSelect t s o
 
 nixHasAttr :: Parser NExpr -> Parser NExpr
 nixHasAttr term = build <$> term <*> optional (reservedOp "?" *> nixSelector) where
@@ -72,7 +71,7 @@ nixTerm = choice
     , nixIf
     , nixBool
     , nixNull
-    , nixPathExpr                 -- can be expensive due to back-tracking
+    , nixPath                 -- can be expensive due to back-tracking
     , try nixLambda <|> nixSet
     , nixStringExpr
     , nixSym
@@ -98,14 +97,11 @@ nixParens = parens nixApp <?> "parens"
 nixList :: Parser NExpr
 nixList = brackets (Fix . NList <$> many (listTerm <* whiteSpace)) <?> "list" where
  listTerm = nixSelect $ choice
-   [ nixInt, nixParens, nixList, nixSet, nixBool, nixNull, nixPathExpr, nixStringExpr
+   [ nixInt, nixParens, nixList, nixSet, nixBool, nixNull, nixPath, nixStringExpr
    , nixSym ]
 
-nixPathExpr :: Parser NExpr
-nixPathExpr = mkPath <$> nixPath
-
-nixPath :: Parser String
-nixPath = (++)
+nixPath :: Parser NExpr
+nixPath = fmap mkPath $ (++)
   <$> try ((++) <$> many (oneOf pathChars) <*> string "/")
   <*> some (oneOf ('/':pathChars))
  where pathChars = ['A'..'Z'] ++ ['a'..'z'] ++ "._-+" ++ ['0'..'9']
diff --git a/tests/ParserTests.hs b/tests/ParserTests.hs
index b135154..f991247 100644
--- a/tests/ParserTests.hs
+++ b/tests/ParserTests.hs
@@ -201,8 +201,11 @@ case_string_antiquote = do
   assertParseFail "${true}"
   assertParseFail "\"${true\""
 
-case_fun_app_path :: Assertion
-case_fun_app_path = assertParseString "f ./." $ Fix $ NApp (mkSym "f") (mkPath "./.")
+case_select_path :: Assertion
+case_select_path = do
+  assertParseString "f ./." $ Fix $ NApp (mkSym "f") (mkPath "./.")
+  assertParseString "f.b ../a" $ Fix $ NApp select (mkPath "../a")
+ where select = Fix $ NSelect (mkSym "f") (mkSelector "b") Nothing
 
 tests :: TestTree
 tests = $testGroupGenerator