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prelude-extras 0.2 → 0.3

raw patch · 11 files changed

+417/−337 lines, 11 files

Files

+ .ghci view
@@ -0,0 +1,1 @@+:set -isrc -idist/build/autogen -optP-include -optPdist/build/autogen/cabal_macros.h
+ .gitignore view
@@ -0,0 +1,13 @@+dist+docs+wiki+TAGS+tags+wip+.DS_Store+.*.swp+.*.swo+*.o+*.hi+*~+*#
.travis.yml view
@@ -1,1 +1,8 @@ language: haskell+notifications:+  irc:+    channels:+      - "irc.freenode.org#haskell-lens"+    skip_join: true+    template:+      - "\x0313prelude-extras\x03/\x0306%{branch}\x03 \x0314%{commit}\x03 %{build_url} %{message}"
+ .vim.custom view
@@ -0,0 +1,31 @@+" Add the following to your .vimrc to automatically load this on startup++" if filereadable(".vim.custom")+"     so .vim.custom+" endif++function StripTrailingWhitespace()+  let myline=line(".")+  let mycolumn = col(".")+  silent %s/  *$//+  call cursor(myline, mycolumn)+endfunction++" enable syntax highlighting+syntax on++" search for the tags file anywhere between here and /+set tags=TAGS;/++" highlight tabs and trailing spaces+set listchars=tab:‗‗,trail:‗+set list++" f2 runs hasktags+map <F2> :exec ":!hasktags -x -c --ignore src"<CR><CR>++" strip trailing whitespace before saving+" au BufWritePre *.hs,*.markdown silent! cal StripTrailingWhitespace()++" rebuild hasktags after saving+au BufWritePost *.hs silent! :exec ":!hasktags -x -c --ignore src"
+ CHANGELOG.markdown view
@@ -0,0 +1,3 @@+0.3+---+* Restructured so users can take advantage of default signatures
LICENSE view
@@ -1,4 +1,4 @@-Copyright 2011 Edward Kmett+Copyright 2011-2013 Edward Kmett  All rights reserved.
− Prelude/Extras.hs 
@@ -1,305 +0,0 @@-{-# LANGUAGE CPP #-}-module Prelude.Extras-  (-  -- * Lifted Prelude classes for kind * -> *-    Eq1(..)-  , Ord1(..)-  , Show1(..), shows1-  , Read1(..), read1, reads1-#ifdef __GLASGOW_HASKELL__-  , readList1Default     -- :: (Read1 f, Read a) => ReadS [f a]-  , readListPrec1Default -- :: (Read1 f, Read a) => ReadPrec [f a]-#endif-  , Lift1(..)-  -- * Lifted Prelude classes for kind * -> * -> *-  , Eq2(..)-  , Ord2(..)-  , Show2(..), shows2-  , Read2(..), read2, reads2-#ifdef __GLASGOW_HASKELL__-  , readList2Default     -- :: (Read1 f, Read a) => ReadS [f a]-  , readListPrec2Default -- :: (Read1 f, Read a) => ReadPrec [f a]-#endif-  , Lift2(..)-  ) where--import Control.Monad (liftM)-import Text.Read-import qualified Text.ParserCombinators.ReadP as P-import qualified Text.Read.Lex as L--infixr 4 ==#,  /=#,  <#,  <=#,  >=#,  >#-infixr 4 ==##, /=##, <##, <=##, >=##, >##--class Eq1 f where-  (==#) :: Eq a => f a -> f a -> Bool-  (/=#) :: Eq a => f a -> f a -> Bool-  a /=# b = not (a ==# b)--instance Eq1 Maybe where-  Just a  ==# Just b  = a == b-  Nothing ==# Nothing = True-  _       ==# _       = False--instance Eq a => Eq1 (Either a) where-  (==#) = (==)--instance Eq1 [] where-  (==#) = (==)-  -class Eq2 f where-  (==##) :: (Eq a, Eq b) => f a b -> f a b -> Bool-  (/=##) :: (Eq a, Eq b) => f a b -> f a b -> Bool-  a /=## b = not (a ==## b)--instance Eq2 Either where-  (==##) = (==)--class Eq1 f => Ord1 f where -  compare1 :: Ord a => f a -> f a -> Ordering-  (<#), (<=#), (>=#), (>#) :: Ord a => f a -> f a -> Bool-  max1, min1 :: Ord a => f a -> f a -> f a--  compare1 x y-    | x ==# y   = EQ-    | x <=# y   = LT-    | otherwise = GT--  x <=# y = compare1 x y /= GT-  x <#  y = compare1 x y == LT-  x >=# y = compare1 x y /= LT-  x ># y  = compare1 x y == GT--  max1 x y -    | x >=# y   = x-    | otherwise = y-  min1 x y-    | x <#  y   = x-    | otherwise = y--instance Ord1 Maybe where compare1 = compare-instance Ord a => Ord1 (Either a) where compare1 = compare-instance Ord1 [] where compare1 = compare---- needs Haskell 2011--- instance Ord1 Complex where compare1 = compare--class Eq2 f => Ord2 f where -  compare2 :: (Ord a, Ord b) => f a b -> f a b -> Ordering-  (<##), (<=##), (>=##), (>##) :: (Ord a, Ord b) => f a b -> f a b -> Bool-  max2, min2 :: (Ord a, Ord b) => f a b -> f a b -> f a b--  compare2 x y-    | x ==## y  = EQ-    | x <=## y  = LT-    | otherwise = GT--  x <=## y = compare2 x y /= GT-  x <##  y = compare2 x y == LT-  x >=## y = compare2 x y /= LT-  x >## y  = compare2 x y == GT--  max2 x y -    | x >=## y  = x-    | otherwise = y-  min2 x y-    | x <## y   = x-    | otherwise = y--instance Ord2 Either where compare2 = compare--class Show1 f where-  showsPrec1 :: Show a => Int -> f a -> ShowS-  show1      :: Show a => f a -> String-  showList1  :: Show a => [f a] -> ShowS-  showsPrec1 _ x s = show1 x ++ s-  show1 x          = shows1 x ""-  showList1 ls   s = showList__ shows1 ls s--shows1 :: (Show1 f, Show a) => f a -> ShowS-shows1 = showsPrec1 0--instance Show1 Maybe where showsPrec1 = showsPrec-instance Show1 [] where showsPrec1 = showsPrec-instance Show a => Show1 (Either a) where showsPrec1 = showsPrec-instance Show a => Show1 ((,) a) where showsPrec1 = showsPrec---- instance Show1 Complex--class Show2 f where -  showsPrec2 :: (Show a, Show b) => Int -> f a b -> ShowS-  show2      :: (Show a, Show b) => f a b -> String-  showList2  :: (Show a, Show b) => [f a b] -> ShowS--  showsPrec2 _ x s = show2 x ++ s-  show2 x          = shows2 x ""-  showList2 ls   s = showList__ shows2 ls s--shows2 :: (Show2 f, Show a, Show b) => f a b -> ShowS-shows2 = showsPrec2 0--instance Show2 (,)    where showsPrec2 = showsPrec-instance Show2 Either where showsPrec2 = showsPrec--showList__ :: (a -> ShowS) ->  [a] -> ShowS-showList__ _     []     s = "[]" ++ s-showList__ showx (x:xs) s = '[' : showx x (showl xs)-  where-    showl []     = ']' : s-    showl (y:ys) = ',' : showx y (showl ys)---class Read1 f where-  readsPrec1    :: Read a => Int -> ReadS (f a)-  readList1     :: Read a => ReadS [f a]--  readsPrec1 = readPrec_to_S readPrec1-  readList1  = readPrec_to_S (list readPrec1) 0 --#ifdef __GLASGOW_HASKELL__-  readPrec1     :: Read a => ReadPrec (f a)-  readListPrec1 :: Read a => ReadPrec [f a]--  readPrec1     = readS_to_Prec readsPrec1-  readListPrec1 = readS_to_Prec (\_ -> readList1)-#endif--read1  :: (Read1 f, Read a) => String -> f a-read1 s = either error id (readEither1 s)--reads1 :: (Read1 f, Read a) => ReadS (f a)-reads1 = readsPrec1 minPrec--readEither1 :: (Read1 f, Read a) => String -> Either String (f a)-readEither1 s =-  case [ x | (x,"") <- readPrec_to_S read' minPrec s ] of-    [x] -> Right x-    []  -> Left "Prelude.read: no parse"-    _   -> Left "Prelude.read: ambiguous parse"- where-  read' =-    do x <- readPrec1-       lift P.skipSpaces-       return x--#ifdef __GLASGOW_HASKELL__-readList1Default     :: (Read1 f, Read a) => ReadS [f a]-readList1Default = readPrec_to_S readListPrec1 0--readListPrec1Default :: (Read1 f, Read a) => ReadPrec [f a]-readListPrec1Default = list readPrec1-#endif--instance Read1 [] where-  readsPrec1 = readsPrec-  readList1 = readList--instance Read1 Maybe where-  readsPrec1 = readsPrec-  readList1 = readList--instance Read a => Read1 (Either a) where-  readsPrec1 = readsPrec-  readList1 = readList--instance Read a => Read1 ((,) a) where-  readsPrec1 = readsPrec-  readList1 = readList--class Read2 f where-  readsPrec2    :: (Read a, Read b) => Int -> ReadS (f a b)-  readList2     :: (Read a, Read b) => ReadS [f a b]-  readsPrec2    = readPrec_to_S readPrec2-  readList2     = readPrec_to_S (list readPrec2) 0 --#ifdef __GLASGOW_HASKELL__-  readPrec2     :: (Read a, Read b) => ReadPrec (f a b)-  readListPrec2 :: (Read a, Read b) => ReadPrec [f a b]-  readPrec2     = readS_to_Prec readsPrec2-  readListPrec2 = readS_to_Prec (\_ -> readList2)-#endif--instance Read2 (,) where-  readsPrec2 = readsPrec-  readList2 = readList--instance Read2 Either where-  readsPrec2 = readsPrec-  readList2 = readList--read2  :: (Read2 f, Read a, Read b) => String -> f a b-read2 s = either error id (readEither2 s)--reads2 :: (Read2 f, Read a, Read b) => ReadS (f a b)-reads2 = readsPrec2 minPrec--readEither2 :: (Read2 f, Read a, Read b) => String -> Either String (f a b)-readEither2 s =-  case [ x | (x,"") <- readPrec_to_S read' minPrec s ] of-    [x] -> Right x-    []  -> Left "Prelude.read: no parse"-    _   -> Left "Prelude.read: ambiguous parse"- where-  read' =-    do x <- readPrec2-       lift P.skipSpaces-       return x--#ifdef __GLASGOW_HASKELL__-readList2Default :: (Read2 f, Read a, Read b) => ReadS [f a b]-readList2Default = readPrec_to_S readListPrec2 0--readListPrec2Default :: (Read2 f, Read a, Read b) => ReadPrec [f a b]-readListPrec2Default = list readPrec2-#endif---- annoying to hav to copy these from Text.Read-list :: ReadPrec a -> ReadPrec [a]--- ^ @(list p)@ parses a list of things parsed by @p@,--- using the usual square-bracket syntax.-list readx =-  parens-  ( do L.Punc "[" <- lexP-       (listRest False +++ listNext)-  )- where-  listRest started =-    do L.Punc c <- lexP-       case c of-         "]"           -> return []-         "," | started -> listNext-         _             -> pfail--  listNext =-    do x  <- reset readx-       xs <- listRest True-       return (x:xs)--newtype Lift1 f a = Lift1 { lower1 :: f a }--instance Eq1 f   => Eq1 (Lift1 f)   where Lift1 a ==# Lift1 b = a ==# b-instance Ord1 f  => Ord1 (Lift1 f)  where Lift1 a `compare1` Lift1 b = compare1 a b-instance Show1 f => Show1 (Lift1 f) where showsPrec1 d (Lift1 a) = showsPrec1 d a-instance Read1 f => Read1 (Lift1 f) where readPrec1 = liftM Lift1 readPrec1--instance (Eq1 f, Eq a) => Eq (Lift1 f a)       where Lift1 a == Lift1 b = a ==# b-instance (Ord1 f, Ord a) => Ord (Lift1 f a)    where Lift1 a `compare` Lift1 b = compare1 a b-instance (Show1 f, Show a) => Show (Lift1 f a) where showsPrec d (Lift1 a) = showsPrec1 d a-instance (Read1 f, Read a) => Read (Lift1 f a) where readPrec = liftM Lift1 readPrec1--newtype Lift2 f a b = Lift2 { lower2 :: f a b }--instance Eq2 f   => Eq2 (Lift2 f)   where Lift2 a ==## Lift2 b = a ==## b-instance Ord2 f  => Ord2 (Lift2 f)  where Lift2 a `compare2` Lift2 b = compare2 a b-instance Show2 f => Show2 (Lift2 f) where showsPrec2 d (Lift2 a) = showsPrec2 d a-instance Read2 f => Read2 (Lift2 f) where readPrec2 = liftM Lift2 readPrec2--instance (Eq2 f, Eq a)     => Eq1 (Lift2 f a)   where Lift2 a ==# Lift2 b = a ==## b-instance (Ord2 f, Ord a)   => Ord1 (Lift2 f a)  where Lift2 a `compare1` Lift2 b = compare2 a b-instance (Show2 f, Show a) => Show1 (Lift2 f a) where showsPrec1 d (Lift2 a) = showsPrec2 d a-instance (Read2 f, Read a) => Read1 (Lift2 f a) where readPrec1 = liftM Lift2 readPrec2--instance (Eq2 f, Eq a, Eq b)       => Eq (Lift2 f a b)   where Lift2 a == Lift2 b = a ==## b-instance (Ord2 f, Ord a, Ord b)    => Ord (Lift2 f a b)  where Lift2 a `compare` Lift2 b = compare2 a b-instance (Show2 f, Show a, Show b) => Show (Lift2 f a b) where showsPrec d (Lift2 a) = showsPrec2 d a-instance (Read2 f, Read a, Read b) => Read (Lift2 f a b) where readPrec = liftM Lift2 readPrec2
− Text/Read/Extras.hs 
@@ -1,13 +0,0 @@-{-# LANGUAGE CPP #-}-module Text.Read.Extras-  ( Read1(..), read1, reads1-  , Read2(..), read2, reads2-#ifdef __GLASGOW_HASKELL__-  , readList1Default     -- :: (Read1 f, Read a) => ReadS [f a]-  , readListPrec1Default -- :: (Read1 f, Read a) => ReadPrec [f a]-  , readList2Default     -- :: (Read1 f, Read a) => ReadS [f a]-  , readListPrec2Default -- :: (Read1 f, Read a) => ReadPrec [f a]-#endif-  ) where--import Prelude.Extras
− Text/Show/Extras.hs 
@@ -1,6 +0,0 @@-module Text.Show.Extras-  ( Show1(..), shows1-  , Show2(..), shows2-  ) where--import Prelude.Extras
prelude-extras.cabal view
@@ -1,6 +1,6 @@ name:          prelude-extras category:      Polymorphism, Combinators-version:       0.2+version:       0.3 license:       BSD3 cabal-version: >= 1.2 license-file:  LICENSE@@ -9,24 +9,23 @@ stability:     provisional homepage:      http://github.com/ekmett/prelude-extras bug-reports:   http://github.com/ekmett/prelude-extras/issues-copyright:     Copyright (C) 2011 Edward A. Kmett+copyright:     Copyright (C) 2011-2013 Edward A. Kmett synopsis:      Haskell 98 - higher order versions of Prelude classes description:   Haskell 98 - higher order versions of Prelude classes to ease programming with polymorphic recursion and reduce UndecidableInstances   .   See <http://flint.cs.yale.edu/trifonov/papers/sqcc.pdf> for further discussion of the approach taken here. build-type:    Simple-extra-source-files: .travis.yml+extra-source-files:+  .ghci+  .gitignore+  .travis.yml+  .vim.custom+  CHANGELOG.markdown  library-  build-depends:-    base >= 4 && < 5-+  build-depends: base >= 4 && < 5   extensions: CPP-+  hs-source-dirs: src   ghc-options: -Wall--  exposed-modules:-    Prelude.Extras,-    Text.Show.Extras,-    Text.Read.Extras+  exposed-modules: Prelude.Extras
+ src/Prelude/Extras.hs view
@@ -0,0 +1,350 @@+{-# LANGUAGE CPP #-}+#ifdef __GLASGOW_HASKELL__ && __GLASGOW_HASKELL__ > 702+#define DEFAULT_SIGNATURES+{-# LANGUAGE DefaultSignatures #-}+#endif++module Prelude.Extras+  (+  -- * Lifted Prelude classes for kind * -> *+    Eq1(..), (/=#)+  , Ord1(..), (<#), (<=#), (>=#), (>#), max1, min1+  , Show1(..), show1, shows1+  , Read1(..), read1, reads1+#ifdef __GLASGOW_HASKELL__+  , readPrec1            -- :: (Read1 f, Read a) => ReadPrec (f a)+  , readListPrec1        -- :: (Read1 f, Read a) => ReadPrec [f a]+  , readList1Default     -- :: (Read1 f, Read a) => ReadS [f a]+  , readListPrec1Default -- :: (Read1 f, Read a) => ReadPrec [f a]+#endif+  , Lift1(..)+  -- * Lifted Prelude classes for kind * -> * -> *+  , Eq2(..), (/=##)+  , Ord2(..), (<##), (<=##), (>=##), (>##), max2, min2+  , Show2(..), show2, shows2+  , Read2(..), read2, reads2+#ifdef __GLASGOW_HASKELL__+  , readPrec2+  , readListPrec2+  , readList2Default+  , readListPrec2Default+#endif+  , Lift2(..)+  ) where++import Control.Arrow (first)+import Text.Read+import qualified Text.ParserCombinators.ReadP as P+import qualified Text.Read.Lex as L++infixr 4 ==#,  /=#,  <#,  <=#,  >=#,  >#+infixr 4 ==##, /=##, <##, <=##, >=##, >##++class Eq1 f where+  (==#) :: Eq a => f a -> f a -> Bool+#ifdef DEFAULT_SIGNATURES+  default (==#) :: (Eq (f a), Eq a) => f a -> f a -> Bool+  (==#) = (==)+#endif++(/=#) :: (Eq1 f, Eq a) => f a -> f a -> Bool+a /=# b = not (a ==# b)++instance Eq1 Maybe where+  Just a  ==# Just b  = a == b+  Nothing ==# Nothing = True+  _       ==# _       = False++instance Eq a => Eq1 (Either a) where+  (==#) = (==)++instance Eq1 [] where+  (==#) = (==)++class Eq2 f where+  (==##) :: (Eq a, Eq b) => f a b -> f a b -> Bool+#ifdef DEFAULT_SIGNATURES+  default (==##) :: (Eq (f a b), Eq a, Eq b) => f a b -> f a b -> Bool+  (==##) = (==)+#endif++(/=##) :: (Eq2 f, Eq a, Eq b) => f a b -> f a b -> Bool+a /=## b = not (a ==## b)++instance Eq2 Either where+  (==##) = (==)++class Eq1 f => Ord1 f where+  compare1 :: Ord a => f a -> f a -> Ordering+#ifdef DEFAULT_SIGNATURES+  default compare1 :: (Ord (f a), Ord a) => f a -> f a -> Ordering+  compare1 = compare+#endif+++(<#), (<=#), (>=#), (>#) :: (Ord1 f, Ord a) => f a -> f a -> Bool+max1, min1 :: (Ord1 f, Ord a) => f a -> f a -> f a++x <=# y = compare1 x y /= GT+x <#  y = compare1 x y == LT+x >=# y = compare1 x y /= LT+x ># y  = compare1 x y == GT++max1 x y+  | x >=# y   = x+  | otherwise = y+min1 x y+  | x <#  y   = x+  | otherwise = y++instance Ord1 Maybe where compare1 = compare+instance Ord a => Ord1 (Either a) where compare1 = compare+instance Ord1 [] where compare1 = compare++-- needs Haskell 2011+-- instance Ord1 Complex where compare1 = compare++class Eq2 f => Ord2 f where+  compare2 :: (Ord a, Ord b) => f a b -> f a b -> Ordering+#ifdef DEFAULT_SIGNATURES+  default compare2 :: (Ord (f a b), Ord a, Ord b) => f a b -> f a b -> Ordering+  compare2 = compare+#endif+++(<##) :: (Ord2 f, Ord a, Ord b) => f a b -> f a b -> Bool+x <=## y = compare2 x y /= GT+(<=##) :: (Ord2 f, Ord a, Ord b) => f a b -> f a b -> Bool+x <##  y = compare2 x y == LT+(>=##) :: (Ord2 f, Ord a, Ord b) => f a b -> f a b -> Bool+x >=## y = compare2 x y /= LT+(>##) :: (Ord2 f, Ord a, Ord b) => f a b -> f a b -> Bool+x >## y  = compare2 x y == GT++max2 :: (Ord2 f, Ord a, Ord b) => f a b -> f a b -> f a b+max2 x y+  | x >=## y  = x+  | otherwise = y++min2 :: (Ord2 f, Ord a, Ord b) => f a b -> f a b -> f a b+min2 x y+  | x <## y   = x+  | otherwise = y++instance Ord2 Either where compare2 = compare++class Show1 f where+  showsPrec1 :: Show a => Int -> f a -> ShowS+#ifdef DEFAULT_SIGNATURES+  default showsPrec1 :: (Show (f a), Show a) => Int -> f a -> ShowS+  showsPrec1 = showsPrec+#endif+  showList1 :: (Show a) => [f a] -> ShowS+  showList1 ls s = showList__ shows1 ls s++show1 :: (Show1 f, Show a) => f a -> String+show1 x = shows1 x ""+++shows1 :: (Show1 f, Show a) => f a -> ShowS+shows1 = showsPrec1 0++instance Show1 Maybe where showsPrec1 = showsPrec+instance Show1 [] where showsPrec1 = showsPrec+instance Show a => Show1 (Either a) where showsPrec1 = showsPrec+instance Show a => Show1 ((,) a) where showsPrec1 = showsPrec++-- instance Show1 Complex++class Show2 f where+  showsPrec2 :: (Show a, Show b) => Int -> f a b -> ShowS+#ifdef DEFAULT_SIGNATURES+  default showsPrec2 :: (Show (f a b), Show a, Show b) => Int -> f a b -> ShowS+  showsPrec2 = showsPrec+#endif+  showList2  :: (Show a, Show b) => [f a b] -> ShowS+  showList2 ls s = showList__ shows2 ls s++show2      :: (Show2 f, Show a, Show b) => f a b -> String+show2 x = shows2 x ""+++shows2 :: (Show2 f, Show a, Show b) => f a b -> ShowS+shows2 = showsPrec2 0++instance Show2 (,)    where showsPrec2 = showsPrec+instance Show2 Either where showsPrec2 = showsPrec++showList__ :: (a -> ShowS) ->  [a] -> ShowS+showList__ _     []     s = "[]" ++ s+showList__ showx (x:xs) s = '[' : showx x (showl xs)+  where+    showl []     = ']' : s+    showl (y:ys) = ',' : showx y (showl ys)++class Read1 f where+  readsPrec1    :: Read a => Int -> ReadS (f a)+#ifdef DEFAULT_SIGNATURES+  default readsPrec1 :: (Read (f a), Read a) => Int -> ReadS (f a)+  readsPrec1 = readsPrec+#endif++  readList1 :: (Read a) => ReadS [f a]+  readList1  = readPrec_to_S (list readPrec1) 0++#ifdef __GLASGOW_HASKELL__+readPrec1     :: (Read1 f, Read a) => ReadPrec (f a)+readPrec1     = readS_to_Prec readsPrec1++readListPrec1 :: (Read1 f, Read a) => ReadPrec [f a]+readListPrec1 = readS_to_Prec (\_ -> readList1)+#endif++read1  :: (Read1 f, Read a) => String -> f a+read1 s = either error id (readEither1 s)++reads1 :: (Read1 f, Read a) => ReadS (f a)+reads1 = readsPrec1 minPrec++readEither1 :: (Read1 f, Read a) => String -> Either String (f a)+readEither1 s =+  case [ x | (x,"") <- readPrec_to_S read' minPrec s ] of+    [x] -> Right x+    []  -> Left "Prelude.read: no parse"+    _   -> Left "Prelude.read: ambiguous parse"+ where+  read' =+    do x <- readPrec1+       lift P.skipSpaces+       return x++#ifdef __GLASGOW_HASKELL__+readList1Default     :: (Read1 f, Read a) => ReadS [f a]+readList1Default = readPrec_to_S readListPrec1 0++readListPrec1Default :: (Read1 f, Read a) => ReadPrec [f a]+readListPrec1Default = list readPrec1+#endif++instance Read1 [] where+  readsPrec1 = readsPrec+  readList1 = readList++instance Read1 Maybe where+  readsPrec1 = readsPrec+  readList1 = readList++instance Read a => Read1 (Either a) where+  readsPrec1 = readsPrec+  readList1 = readList++instance Read a => Read1 ((,) a) where+  readsPrec1 = readsPrec+  readList1 = readList++class Read2 f where+  readsPrec2    :: (Read a, Read b) => Int -> ReadS (f a b)+#ifdef DEFAULT_SIGNATURES+  default readsPrec2 :: (Read (f a b), Read a, Read b) => Int -> ReadS (f a b)+  readsPrec2 = readsPrec+#endif+  readList2     :: (Read a, Read b) => ReadS [f a b]+  readList2     = readPrec_to_S (list readPrec2) 0++#ifdef __GLASGOW_HASKELL__+readPrec2     :: (Read2 f, Read a, Read b) => ReadPrec (f a b)+readPrec2     = readS_to_Prec readsPrec2++readListPrec2 :: (Read2 f, Read a, Read b) => ReadPrec [f a b]+readListPrec2 = readS_to_Prec (\_ -> readList2)+#endif++instance Read2 (,) where+  readsPrec2 = readsPrec+  readList2 = readList++instance Read2 Either where+  readsPrec2 = readsPrec+  readList2 = readList++read2  :: (Read2 f, Read a, Read b) => String -> f a b+read2 s = either error id (readEither2 s)++reads2 :: (Read2 f, Read a, Read b) => ReadS (f a b)+reads2 = readsPrec2 minPrec++readEither2 :: (Read2 f, Read a, Read b) => String -> Either String (f a b)+readEither2 s =+  case [ x | (x,"") <- readPrec_to_S read' minPrec s ] of+    [x] -> Right x+    []  -> Left "Prelude.read: no parse"+    _   -> Left "Prelude.read: ambiguous parse"+ where+  read' =+    do x <- readPrec2+       lift P.skipSpaces+       return x++#ifdef __GLASGOW_HASKELL__+readList2Default :: (Read2 f, Read a, Read b) => ReadS [f a b]+readList2Default = readPrec_to_S readListPrec2 0++readListPrec2Default :: (Read2 f, Read a, Read b) => ReadPrec [f a b]+readListPrec2Default = list readPrec2+#endif++-- annoying to hav to copy these from Text.Read+list :: ReadPrec a -> ReadPrec [a]+-- ^ @(list p)@ parses a list of things parsed by @p@,+-- using the usual square-bracket syntax.+list readx =+  parens+  ( do L.Punc "[" <- lexP+       (listRest False +++ listNext)+  )+ where+  listRest started =+    do L.Punc c <- lexP+       case c of+         "]"           -> return []+         "," | started -> listNext+         _             -> pfail++  listNext =+    do x  <- reset readx+       xs <- listRest True+       return (x:xs)++newtype Lift1 f a = Lift1 { lower1 :: f a }++instance Eq1 f   => Eq1 (Lift1 f)   where Lift1 a ==# Lift1 b = a ==# b+instance Ord1 f  => Ord1 (Lift1 f)  where Lift1 a `compare1` Lift1 b = compare1 a b+instance Show1 f => Show1 (Lift1 f) where showsPrec1 d (Lift1 a) = showsPrec1 d a+instance Read1 f => Read1 (Lift1 f) where+  readsPrec1 d = map (first Lift1) . readsPrec1 d++instance (Eq1 f, Eq a) => Eq (Lift1 f a)       where Lift1 a == Lift1 b = a ==# b+instance (Ord1 f, Ord a) => Ord (Lift1 f a)    where Lift1 a `compare` Lift1 b = compare1 a b+instance (Show1 f, Show a) => Show (Lift1 f a) where showsPrec d (Lift1 a) = showsPrec1 d a+instance (Read1 f, Read a) => Read (Lift1 f a) where+  readsPrec d = map (first Lift1) . readsPrec1 d++newtype Lift2 f a b = Lift2 { lower2 :: f a b }++instance Eq2 f   => Eq2 (Lift2 f)   where Lift2 a ==## Lift2 b = a ==## b+instance Ord2 f  => Ord2 (Lift2 f)  where Lift2 a `compare2` Lift2 b = compare2 a b+instance Show2 f => Show2 (Lift2 f) where showsPrec2 d (Lift2 a) = showsPrec2 d a+instance Read2 f => Read2 (Lift2 f) where+  readsPrec2 d = map (first Lift2) . readsPrec2 d++instance (Eq2 f, Eq a)     => Eq1 (Lift2 f a)   where Lift2 a ==# Lift2 b = a ==## b+instance (Ord2 f, Ord a)   => Ord1 (Lift2 f a)  where Lift2 a `compare1` Lift2 b = compare2 a b+instance (Show2 f, Show a) => Show1 (Lift2 f a) where showsPrec1 d (Lift2 a) = showsPrec2 d a+instance (Read2 f, Read a) => Read1 (Lift2 f a) where+  readsPrec1 d = map (first Lift2) . readsPrec2 d++instance (Eq2 f, Eq a, Eq b)       => Eq (Lift2 f a b)   where Lift2 a == Lift2 b = a ==## b+instance (Ord2 f, Ord a, Ord b)    => Ord (Lift2 f a b)  where Lift2 a `compare` Lift2 b = compare2 a b+instance (Show2 f, Show a, Show b) => Show (Lift2 f a b) where showsPrec d (Lift2 a) = showsPrec2 d a+instance (Read2 f, Read a, Read b) => Read (Lift2 f a b) where+  readsPrec d = map (first Lift2) . readsPrec2 d