{-# OPTIONS_GHC -fno-warn-orphans #-} {-# LANGUAGE FlexibleInstances, MagicHash, OverlappingInstances, TemplateHaskell, TypeSynonymInstances #-} {-| Module: HaskHOL.Core.Lib.Lift Copyright: (c) Ian Lynagh 2006 LICENSE: BSD3 Maintainer: ecaustin@ittc.ku.edu Stability: unstable Portability: unknown This module is a re-export of the th-lift library originally written by Ian Lynagh and maintained by Mathieu Boespflug. A very minor change was made by Evan Austin in order to facilitate derivation of lift instances for quantified type constructors. The decision to include this source as part of the HaskHOL system, rather than import the original library, was made to facilitate the above change and to sever HaskHOL's only dependence on a non-Haskell Platform library. -} {- The original copyright is included in its entirety below, as required by BSD3: Copyright (c) Ian Lynagh. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The names of the author may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -} module HaskHOL.Core.Lib.Lift ( deriveLift' -- :: Info -> Q [Dec] , deriveLift -- :: Name -> Q [Dec] , deriveLiftMany -- :: [Name] -> Q [Dec] , module TH {-| Re-exports 'Lift' for the purpose of writing type signatures external to this module. -} ) where import GHC.Exts import Language.Haskell.TH import Language.Haskell.TH.Syntax import qualified Language.Haskell.TH.Syntax as TH (Lift) import Control.Monad ((<=<)) -- | Derive Lift instances for the given datatype. deriveLift :: Name -> Q [Dec] deriveLift = deriveLift' <=< reify -- | Derive Lift instances for many datatypes. deriveLiftMany :: [Name] -> Q [Dec] deriveLiftMany = deriveLiftMany' <=< mapM reify -- | Obtain Info values through a custom reification function. This is useful -- when generating instances for datatypes that have not yet been declared. deriveLift' :: Info -> Q [Dec] deriveLift' = fmap (:[]) . deriveLiftOne deriveLiftMany' :: [Info] -> Q [Dec] deriveLiftMany' = mapM deriveLiftOne deriveLiftOne :: Info -> Q Dec deriveLiftOne i = case i of TyConI (DataD dcx n vsk cons _) -> liftInstance dcx n (map unTyVarBndr vsk) (map doCons cons) TyConI (NewtypeD dcx n vsk con _) -> liftInstance dcx n (map unTyVarBndr vsk) [doCons con] _ -> fail ("deriveLift: unhandled: " ++ pprint i) where liftInstance dcx n vs cases = instanceD (ctxt dcx vs) (conT ''Lift `appT` typ n vs) [funD 'lift cases] typ n = foldl appT (conT n) . map varT ctxt dcx = fmap (dcx ++) . cxt . map liftPred unTyVarBndr (PlainTV v) = v unTyVarBndr (KindedTV v _) = v liftPred n = classP ''Lift [varT n] doCons :: Con -> Q Clause doCons (NormalC c sts) = do let ns = zipWith (\_ i -> 'x' : show i) sts [(0::Integer)..] con = [| conE c |] args = [ [| lift $(varE (mkName n)) |] | n <- ns ] e = foldl (\e1 e2 -> [| appE $e1 $e2 |]) con args clause [conP c (map (varP . mkName) ns)] (normalB e) [] doCons (RecC c sts) = doCons $ NormalC c [(s, t) | (_, s, t) <- sts] doCons (InfixC sty1 c sty2) = do let con = [| conE c |] left = [| lift $(varE (mkName "x0")) |] right = [| lift $(varE (mkName "x1")) |] e = [| infixApp $left $con $right |] clause [infixP (varP (mkName "x0")) c (varP (mkName "x1"))] (normalB e) [] -- ECA doCons (ForallC _ _ con) = doCons con instance Lift Name where lift (Name occName nameFlavour) = [| Name occName nameFlavour |] instance Lift OccName where lift n = [| mkOccName $(lift $ occString n) |] instance Lift PkgName where lift n = [| mkPkgName $(lift $ pkgString n) |] instance Lift ModName where lift n = [| mkModName $(lift $ modString n) |] instance Lift NameFlavour where lift NameS = [| NameS |] lift (NameQ moduleName) = [| NameQ moduleName |] lift (NameU i) = [| case $( lift (I# i) ) of I# i' -> NameU i' |] lift (NameL i) = [| case $( lift (I# i) ) of I# i' -> NameL i' |] lift (NameG nameSpace pkgName moduleName) = [| NameG nameSpace pkgName moduleName |] instance Lift NameSpace where lift VarName = [| VarName |] lift DataName = [| DataName |] lift TcClsName = [| TcClsName |] -- These instances should really go in the template-haskell package. instance Lift () where lift _ = [| () |] instance Lift Rational where lift x = return (LitE (RationalL x)) --ECA instance Lift String where lift = liftString