[WIP] Rework

README.md

@@ -35,7 +35,6 @@ Run `bin/test` for fast-reloading tests. When library sources change, the test s
 * Documentation.
 * Expose all internals.
 * `-- NOTE: doesn't use 'KeyDoesNotExist'` — fix this.
-* `RemoveAccessTo` — can we get rid of it?
 
 ## Acknowledgement
 

Setup.hs

@@ -1,2 +1,6 @@
-import Distribution.Simple
-main = defaultMain
+module Main where
+
+import Distribution.Extra.Doctest (defaultMainWithDoctests)
+
+main :: IO ()
+main = defaultMainWithDoctests "doctests"

bin/genrecord

@@ -14,6 +14,9 @@ main = do
   putStrLn
     "-- Generated with cabal run -v0 bin/genrecord > src/JRec/Tuple.hs\n\
     \\n\
+    \{-# LANGUAGE TypeOperators, DataKinds, FlexibleInstances, MultiParamTypeClasses #-}\n\
+    \{-# LANGUAGE FunctionalDependencies, GADTs, UndecidableInstances #-}\n\
+    \\n\
     \module JRec.Tuple where\n\
     \\n\
     \import qualified JRec.Internal as R\n\
@@ -46,10 +49,7 @@ genInstance i =
           exprList
           exprTuple
       constraints =
-        tupleF $
-          format "R.RecApply {} {} R.NoConstraint" typeList typeList :
-          [format "n{} ~ n{}'" j j :: Builder | j <- [1 .. i]]
-            ++ [format "v{} ~ v{}'" j j :: Builder | j <- [1 .. i]]
+        tupleF [format "(n{} R.:= v{}) ~ f{}" j j j :: Builder | j <- [1 .. i]]
    in format
         "instance {} => RecTuple {} {} where\n\
         \  {}\n\
@@ -61,8 +61,8 @@ genInstance i =
         fromTuple
         toTuple
   where
-    -- '[n1' R.:= v1', n2' R.:= v2']
-    typeList = "'" <> listF [format "n{}' R.:= v{}'" j j :: Builder | j <- [1 .. i]]
+    -- '[f1, f2]
+    typeList = "'" <> listF ["f" <> show j | j <- [1 .. i]]
     -- (n1 R.:= v1, n2 R.:= v2)
     typeTuple = tupleF [format "n{} R.:= v{}" j j :: Builder | j <- [1 .. i]]
     -- (f1, f2)

bin/test

@@ -1,5 +1,4 @@
 #!/usr/bin/env bash
 set -xe
 
-# NOTE: ghcid should be run with -W to allow warnings from should-not-typecheck
-nix-shell --pure --run "ghcid $* -W -c 'cabal new-repl test:jrec-test' -T \":main $*\""
+nix-shell --pure --run "ghcid $* -c 'cabal new-repl test:jrec-test' -T \":main $*\""

default.nix

@@ -30,6 +30,9 @@ in {
         packages = p: [ p.jrec ];
         buildInputs = with projectDrv; [
           cabal-install
+          ormolu
+          haskell-language-server
+          ghcid
         ];
       };
   in 

jrec.cabal

@@ -12,11 +12,17 @@ maintainer:         artyom.kazak@juspay.in
 
 -- copyright:
 -- category:
-build-type:         Simple
+build-type:         Custom
 extra-source-files:
   CHANGELOG.md
   README.md
 
+custom-setup
+  setup-depends:
+      base
+    , Cabal
+    , cabal-doctest  >=1.0.8 && <1.1
+
 flag with-aeson
   description: Enable Aeson instances
   -- don't let the solver fiddle with the flag
@@ -41,34 +47,6 @@ common library-common
     , lens
     , mtl
     , text
-  default-extensions:
-    BlockArguments
-    DataKinds
-    DeriveGeneric
-    DerivingStrategies
-    DuplicateRecordFields
-    FlexibleContexts
-    FlexibleInstances
-    FunctionalDependencies
-    GADTs
-    InstanceSigs
-    KindSignatures
-    LambdaCase
-    MultiParamTypeClasses
-    OverloadedLabels
-    OverloadedStrings
-    PatternSynonyms
-    RankNTypes
-    ScopedTypeVariables
-    StandaloneDeriving
-    TupleSections
-    TypeFamilies
-    TypeOperators
-    UndecidableInstances
-    UnicodeSyntax
-    ViewPatterns
-    ConstraintKinds
-    PackageImports
 
 library
   import: library-common
@@ -78,18 +56,31 @@ library
     JRec.Internal
   other-modules:
     JRec.Tuple
-    JRec.Field
   if flag(with-aeson)
     cpp-options: -DWITH_AESON
 
 test-suite jrec-test
   import: library-common
   type: exitcode-stdio-1.0
-  hs-source-dirs: test, src
+  hs-source-dirs: test
   main-is: Spec.hs 
   build-depends:
+    jrec,
     base,
     hspec,
     QuickCheck,
-    lens,
-    should-not-typecheck
+    lens
+
+test-suite doctests
+  type:             exitcode-stdio-1.0
+  main-is:          doctests.hs
+  build-depends:
+      base
+    , base-compat
+    , doctest
+    , QuickCheck
+    , jrec
+    , template-haskell
+  ghc-options:      -Wall -threaded
+  hs-source-dirs:   test
+  default-language: Haskell2010

src/JRec.hs

@@ -1,6 +1,17 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE GADTs #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE PackageImports #-}
 {-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE TypeFamilies #-}
 
 module JRec
   ( unField,
@@ -10,7 +21,7 @@ module JRec
     append,
     union,
     insert,
-    insertOrSet
+    insertOrSet,
   )
 where
 
@@ -25,12 +36,15 @@ import GHC.Generics
 import GHC.OverloadedLabels
 import GHC.TypeLits
 import Generic.Data
-import JRec.Field
-import JRec.Internal (Rec, (:=) (..))
+import JRec.Internal (Rec, append, (:=) (..))
 import qualified JRec.Internal as R
 import JRec.Tuple
 import Unsafe.Coerce
 
+-- $setup
+--
+-- >>> :set -XOverloadedLabels
+
 ----------------------------------------------------------------------------
 -- unField
 ----------------------------------------------------------------------------
@@ -42,29 +56,10 @@ unField _ (_ R.:= value) = value
 -- Other operations
 ----------------------------------------------------------------------------
 
--- Appends records, without removing duplicates.
+-- | Merges records, removing duplicates
 --
--- O(n + m) type check complexity.
+-- Left-biased. Does not sort.
 --
--- FIXME: See spec for a bug when there are duplicates.
-append ::
-  forall lhs rhs res.
-  ( KnownNat (R.RecSize lhs),
-    KnownNat (R.RecSize rhs),
-    KnownNat (R.RecSize lhs + R.RecSize rhs),
-    res ~ R.RecAppend lhs rhs,
-    R.RecCopy lhs lhs res,
-    R.RecCopy rhs rhs res
-  ) =>
-  Rec lhs ->
-  Rec rhs ->
-  Rec res
-append = R.combine
-
--- Merges records, removing duplicates
---
--- Left-biased. Does not sort. 
--- 
 -- O(n * m) type check complexity.
 union ::
   forall lhs rhs res.
@@ -80,21 +75,29 @@ union ::
   Rec res
 union = R.union
 
--- | Insert a field into a record that does not already contain it
+-- | Insert a field into a record.
 --
 -- O(n) type check complexity.
-insert :: 
-  forall label value lts res. 
+--
+-- Will fail at compile time if the record already contains the field:
+--
+-- >>> (#a := '1') `insert` Rec (#b := '2', #a := '0')
+-- ...
+-- ... Duplicate key "a"
+-- ...
+insert ::
+  forall label value lts res.
   ( KnownNat (1 + R.RecSize lts),
     KnownNat (R.RecSize lts),
     KnownSymbol label,
     R.RecCopy lts lts res,
     res ~ ((label := value) : lts),
-    R.RemoveAccessTo label lts ~ lts
-  ) => 
+    R.KeyDoesNotExist label lts
+  ) =>
   label := value ->
-  Rec lts -> Rec res
-insert = R.combine . Rec 
+  Rec lts ->
+  Rec res
+insert = R.append . Rec
 
 -- | Insert a field into a record. Set it if it already exists
 --