labels 0.1.2 → 0.2.0

raw patch · 4 files changed

+85/−14 lines, 4 filesdep ~basePVP ok

version bump matches the API change (PVP)

Dependency ranges changed: base

API changes (from Hackage documentation)

Files

• CHANGELOG +4/−0
• labels.cabal +2/−2
• src/Labels.hs +15/−1
• src/Labels/Internal.hs +64/−11

@@ -1,3 +1,7 @@+0.2.0:+	* Add "reflect" and "labels" functions.+	* Drop support for GHC <8.+ 0.1.2: 	* Add docs for "project" function. 

@@ -1,5 +1,5 @@ name:                labels-version:             0.1.2+version:             0.2.0 synopsis:            Anonymous records via named tuples description:         Declare and access tuple fields with labels. An approach to anonymous records. homepage:            https://github.com/chrisdone/labels#readme@@ -19,7 +19,7 @@   ghc-options:         -Wall -O2   exposed-modules:     Labels,                        Labels.Internal-  build-depends:       base >= 4.7 && < 5,+  build-depends:       base >= 4.9.0.0 && < 5,                        template-haskell   default-language:    Haskell2010 

@@ -3,6 +3,7 @@ {-# LANGUAGE KindSignatures #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE Rank2Types #-}+{-# LANGUAGE OverloadedLabels #-} -- | Labels for fields in a tuple. -- -- Enable these extensions:@@ -64,6 +65,16 @@ -- -- >>> project (#bar := "hello", #foo := 3) :: ("foo" := Int, "bar" := String) -- (#foo := 3,#bar := "hello")+--+-- Reflection of labels+--+-- >>> labels (#bar := "hello", #foo := 3, #mu := "hi")+-- ["bar","foo","mu"]+--+-- Reflection of labelled fields+--+-- >>> reflect @Show show (#bar := "hello", #foo := 3, #mu := "hi")+-- [("bar","\"hello\""),("foo","3"),("mu","\"hi\"")]  module Labels -- Field access@@ -73,11 +84,14 @@   , lens   , cons   , project+  , reflect+  , labels    -- Construction   , (:=)(..)   , Has   , Cons-  , Project)+  , Project+  , Reflect)   where  import Data.Proxy

@@ -1,3 +1,6 @@+{-# LANGUAGE TypeApplications #-}+{-# LANGUAGE ConstraintKinds #-}+{-# LANGUAGE Rank2Types #-} {-# LANGUAGE BangPatterns #-} {-# LANGUAGE CPP #-} {-# LANGUAGE TypeFamilies #-}@@ -12,11 +15,11 @@ {-# LANGUAGE KindSignatures #-} {-# LANGUAGE TemplateHaskell #-} {-# LANGUAGE FlexibleInstances #-}-#if __GLASGOW_HASKELL__ >= 800-{-# LANGUAGE OverloadedLabels #-}-#endif {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE AllowAmbiguousTypes #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE OverloadedLabels #-}+ {-# OPTIONS_GHC -fno-warn-orphans #-}  -- | This module provides a way to name the fields in a regular@@ -26,14 +29,10 @@  import Data.Data import Data.String+import GHC.Exts import GHC.TypeLits import Language.Haskell.TH--#if __GLASGOW_HASKELL__ >= 800 import GHC.OverloadedLabels-#else-import Data.Proxy-#endif  -------------------------------------------------------------------------------- -- A labelled value@@ -61,12 +60,10 @@ -------------------------------------------------------------------------------- -- Labels -#if __GLASGOW_HASKELL__ >= 800 instance l ~ l' =>          IsLabel (l :: Symbol) (Proxy l') where     fromLabel _ = Proxy     {-# INLINE fromLabel #-}-#endif  instance IsString (Q Exp) where   fromString str = [|Proxy :: Proxy $(litT (return (StrTyLit str)))|]@@ -106,11 +103,67 @@ -- | A record can be narrowed or have its order changed by projecting -- into record type. class Project from to where-  -- | Narrow number of or change order of fields in a record.+  -- | Narrow number of or change order of fields in a record:+  -- Example: @project (#foo := 1, #bar := 2) :: ("bar" := Int)@   project :: from -> to  --------------------------------------------------------------------------------+-- Key-value reflection++-- | Reflection on labelled fields.+class Reflect (c :: * -> Constraint) r where+  -- | Produce a list of field names, and each field applied to the+  -- given function. Example: @reflect \@Show show (#bar := "hello", #foo := 3)@+  reflect :: forall b. (forall a. c a => a -> b) -> r -> [(String, b)]++--------------------------------------------------------------------------------+-- Field reflection++-- | A constraint and a method which both simply ignore their+-- argument.+class Ignore a where ignore :: a -> ()+instance Ignore a where ignore _ = ()++-- | List the field labels present in the record. Example: @labels+-- (#bar := "hello", #foo := 3, #mu := "hi")@+labels :: Reflect Ignore r => r -> [String]+labels r = map fst (reflect @Ignore ignore r)++-------------------------------------------------------------------------------- -- TH-derived instances++-- Generate Reflect instances.+$(let labelt i = varT (mkName ("l" ++ show i))+      labelp i = varP (mkName ("l" ++ show i))+      labelv i = varE (mkName ("l" ++ show i))+      valuet i = varT (mkName ("v" ++ show i))+      valuev i = varE (mkName ("v" ++ show i))+      valuep i = varP (mkName ("v" ++ show i))+      c = varT (mkName "c")+      fp = varP (mkName "f")+      fv = varE (mkName "f")+  in sequence+       [ instanceD+         (sequence [[t|$(c) $(valuet i)|] | i <- [1 :: Int .. n]])+         [t|Reflect $(c) $(foldl+                             appT+                             (tupleT n)+                             [[t|$(labelt i) := $(valuet i)|] | i <- [1 .. n]])|]+         [ funD+             'reflect+             [ clause+                 [fp, tupP [conP '(:=) [labelp i,valuep i] | i <- [1 .. n]]]+                 (normalB+                    (listE+                       [ [|(symbolVal $(labelv i), $(fv) $(valuev i))|]+                       | i <- [1 .. n]+                       ]))+                 []+             ]+         , return (PragmaD (InlineP 'reflect Inline FunLike AllPhases))+         ]+       | n <- [1 .. 24]+       ])  -- Generate Cons instances. $(let makeInstance size =