Merge pull request #56 from Profpatsch/mkDots-automatic-symbol-quoting

mkDots automatic symbol quoting

Nix/Expr/Shorthands.hs

@@ -11,6 +11,8 @@ import Data.Fix
 import qualified Data.Map as Map
 import Nix.Atoms
 import Nix.Expr.Types
+import Text.Regex.TDFA.Text ()
+import Text.Regex.TDFA ((=~))
 
 -- | Make an integer literal expression.
 mkInt :: Integer -> NExpr
@@ -126,10 +128,21 @@ mkFunction :: Params NExpr -> NExpr -> NExpr
 mkFunction params = Fix . NAbs params
 
 mkDot :: NExpr -> Text -> NExpr
-mkDot e key = Fix $ NSelect e [StaticKey key] Nothing
+mkDot e key = mkDots e [key]
 
 mkDots :: NExpr -> [Text] -> NExpr
-mkDots e keys = Fix $ NSelect e (StaticKey <$> keys) Nothing
+mkDots e keys = Fix $ NSelect e (toKey <$> keys) Nothing
+  where
+    toKey :: Text -> NKeyName NExpr
+    toKey k = (if isPlainSymbol k then StaticKey else dynamicKey) k
+    -- | Make a dynamic key name that is only enclosed in double quotes
+    -- (no antiquotes).
+    dynamicKey :: Text -> NKeyName NExpr
+    dynamicKey k = DynamicKey $ Plain $ DoubleQuoted [Plain k]
+    -- | Check if it’s a valid nix symbol
+    -- the nix lexer regex for IDs (symbols) is [a-zA-Z\_][a-zA-Z0-9\_\'\-]*
+    isPlainSymbol :: Text -> Bool
+    isPlainSymbol s = s =~ ("^[a-zA-Z_][a-zA-Z0-9_'-]*$" :: Text)
 
 -- | An `inherit` clause without an expression to pull from.
 inherit :: [NKeyName e] -> Binding e

default.nix

@@ -1,6 +1,9 @@
-{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc801" }:
+{ nixpkgs ? import <nixpkgs> {}, compiler ? null }:
 let
-  haskellPackages = nixpkgs.pkgs.haskell.packages.${compiler};
+  haskellPackages = if compiler == null
+                    # use the current default version
+                    then nixpkgs.pkgs.haskellPackages
+                    else nixpkgs.pkgs.haskell.packages.${compiler};
 in
 
 haskellPackages.callPackage ./project.nix {

hnix.cabal

@@ -62,6 +62,8 @@ Library
     , data-fix
     , deepseq
     , semigroups >= 0.18 && < 0.19
+    , regex-tdfa
+    , regex-tdfa-text
   if flag(parsec)
     Cpp-options: -DUSE_PARSEC
     Build-depends: parsec

project.nix

@@ -1,6 +1,7 @@
 { mkDerivation, ansi-wl-pprint, base, containers, data-fix, deepseq
 , parsers, stdenv, tasty, tasty-hunit, tasty-th, text, transformers
 , trifecta, unordered-containers, criterion, pkgs, deriving-compat
+, regex-tdfa, regex-tdfa-text
 }:
 
 let
@@ -19,6 +20,7 @@ mkDerivation {
   libraryHaskellDepends = [
     ansi-wl-pprint base containers data-fix deepseq parsers text
     transformers trifecta unordered-containers criterion deriving-compat
+    regex-tdfa regex-tdfa-text
   ];
   executableHaskellDepends = [
     ansi-wl-pprint base containers data-fix deepseq

tests/Main.hs

@@ -4,6 +4,7 @@ import Test.Tasty
 
 import qualified ParserTests
 import qualified EvalTests
+import qualified ShorthandTests
 
 import Prelude (IO, ($))
 
@@ -11,4 +12,5 @@ main :: IO ()
 main = defaultMain $ testGroup "hnix"
   [ ParserTests.tests
   , EvalTests.tests
+  , ShorthandTests.tests
   ]

tests/ShorthandTests.hs

@@ -0,0 +1,39 @@
+{-# LANGUAGE TemplateHaskell, OverloadedStrings #-}
+module ShorthandTests (tests) where
+
+import Prelude
+
+import Test.Tasty
+import Test.Tasty.HUnit
+import Test.Tasty.TH
+
+import Control.Monad (forM_)
+import Data.Monoid ((<>))
+import Data.Fix
+
+import Nix.Expr
+
+
+case_mkDotsSymbolEscaping :: Assertion
+case_mkDotsSymbolEscaping = do
+  let check xs errmsg assert =
+        forM_ xs $ \x -> assertBool (errmsg <> ": " <> show x) $ assert x
+  check plain "not a plain value" $ assertIsSingle
+  check nonPlain "not a non-plain value" $ not . assertIsSingle
+  where
+    plain = [ "abc09", "_A_'-", "AbC" ]
+    nonPlain = [ "abc def", "\\", "'abc", "\"", "-foo", "a.b.c" ]
+    assertIsSingle = isPlainSingle . getKey . mkDot "dummy"
+    getKey (Fix (NSelect _ [key] _)) = key
+    getKey _ = error "invalid"
+    isPlainSingle (StaticKey _) = True
+    isPlainSingle (DynamicKey (Plain (DoubleQuoted [Plain _]))) = False
+    isPlainSingle _ = error "invalid"
+
+
+---------------------------
+
+tests :: TestTree
+tests = $(testGroupGenerator)
+
+