ghc-mod/NotCPP/Declarations.hs

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-- ghc-mod: Happy Haskell Hacking
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-- Copyright (C) 2015 Daniel Gröber <dxld ÄT darkboxed DOT org>
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU Affero General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU Affero General Public License for more details.
--
-- You should have received a copy of the GNU Affero General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
{-# OPTIONS_GHC -fno-warn-unused-imports #-}
{-# LANGUAGE CPP #-}
-- Using CPP so you don't have to :)
module NotCPP.Declarations where
import Control.Arrow
import Control.Applicative
import Data.Maybe
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import Language.Haskell.TH.Syntax
import NotCPP.LookupValueName
nT :: Monad m => String -> m Type
cT :: Monad m => String -> m Type
nE :: Monad m => String -> m Exp
nP :: Monad m => String -> m Pat
nT str = return $ VarT (mkName str)
cT str = return $ ConT (mkName str)
nE str = return $ VarE (mkName str)
nP str = return $ VarP (mkName str)
recUpdE' :: Q Exp -> Name -> Exp -> Q Exp
recUpdE' ex name assign = do
RecUpdE <$> ex <*> pure [(name, assign)]
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lookupName' :: (NameSpace, String) -> Q (Maybe Name)
lookupName' (VarName, n) = lookupValueName n
lookupName' (DataName, n) = lookupValueName n
lookupName' (TcClsName, n) = lookupTypeName n
-- Does this even make sense?
ifelseD :: Q [Dec] -> Q [Dec] -> Q [Dec]
ifelseD if_decls' else_decls = do
if_decls <- if_decls'
alreadyDefined <- definedNames (boundNames `concatMap` if_decls)
case alreadyDefined of
[] -> if_decls'
_ -> else_decls
ifdefelseD, ifelsedefD :: String -> Q [Dec] -> Q [Dec] -> Q [Dec]
ifelsedefD = ifdefelseD
ifdefelseD ident if_decls else_decls = do
exists <- isJust <$> lookupValueName ident
if exists
then if_decls
else else_decls
ifdefD :: String -> Q [Dec] -> Q [Dec]
ifdefD ident decls = ifdefelseD ident decls (return [])
ifndefD :: String -> Q [Dec] -> Q [Dec]
ifndefD ident decls = ifdefelseD ident (return []) decls
-- | Each of the given declarations is only spliced if the identifier it defines
-- is not defined yet.
--
-- For example:
--
-- @$(ifD [[d| someFunctionThatShouldExist x = x+1 |]]@
--
-- If @someFunctionThatShouldExist@ doesn't actually exist the definition given
-- in the splice will be the result of the splice otherwise nothing will be
-- spliced.
--
-- Currently this only works for function declarations but it can be easily
-- extended to other kinds of declarations.
ifD :: Q [Dec] -> Q [Dec]
ifD decls' = do
decls <- decls'
concat <$> flip mapM decls (\decl -> do
alreadyDefined <- definedNames (boundNames decl)
case alreadyDefined of
[] -> return [decl]
_ -> return [])
definedNames :: [(NameSpace, Name)] -> Q [Name]
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definedNames ns = catMaybes <$> (lookupName' . second nameBase) `mapM` ns
boundNames :: Dec -> [(NameSpace, Name)]
boundNames decl =
case decl of
SigD n _ -> [(VarName, n)]
FunD n _cls -> [(VarName, n)]
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#if __GLASGOW_HASKELL__ >= 706
InfixD _ n -> [(VarName, n)]
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#endif
ValD p _ _ -> map ((,) VarName) $ patNames p
TySynD n _ _ -> [(TcClsName, n)]
ClassD _ n _ _ _ -> [(TcClsName, n)]
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#if __GLASGOW_HASKELL__ >= 800
DataD _ n _ _ ctors _ ->
#else
DataD _ n _ ctors _ ->
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#endif
[(TcClsName, n)] ++ map ((,) TcClsName) (conNames `concatMap` ctors)
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#if __GLASGOW_HASKELL__ >= 800
NewtypeD _ n _ _ ctor _ ->
#else
NewtypeD _ n _ ctor _ ->
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#endif
[(TcClsName, n)] ++ map ((,) TcClsName) (conNames ctor)
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#if __GLASGOW_HASKELL__ >= 800
DataInstD _ _n _ _ ctors _ ->
#else
DataInstD _ _n _ ctors _ ->
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#endif
map ((,) TcClsName) (conNames `concatMap` ctors)
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#if __GLASGOW_HASKELL__ >= 800
NewtypeInstD _ _n _ _ ctor _ ->
#else
NewtypeInstD _ _n _ ctor _ ->
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#endif
map ((,) TcClsName) (conNames ctor)
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InstanceD {} -> -- _ _ty _
error "notcpp: Instance declarations are not supported yet"
ForeignD _ ->
error "notcpp: Foreign declarations are not supported yet"
PragmaD _pragma -> error "notcpp: pragmas are not supported yet"
#if __GLASGOW_HASKELL__ >= 708
TySynInstD _n _ -> error "notcpp: TySynInstD not supported yet"
#else
TySynInstD _n _ _ -> error "notcpp: TySynInstD not supported yet"
#endif
#if __GLASGOW_HASKELL__ >= 708
RoleAnnotD _n _ -> error "notcpp: RoleAnnotD not supported yet"
#endif
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#if __GLASGOW_HASKELL__ >= 704 && __GLASGOW_HASKELL__ < 800
FamilyD _ n _ _ -> [(TcClsName, n)]
#elif __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 800
ClosedTypeFamilyD n _ _ _ -> [(TcClsName, n)]
#else
OpenTypeFamilyD (TypeFamilyHead n _ _ _) -> [(TcClsName, n)]
ClosedTypeFamilyD (TypeFamilyHead n _ _ _) _ -> [(TcClsName, n)]
#endif
conNames :: Con -> [Name]
conNames con =
case con of
NormalC n _ -> [n]
RecC n _ -> [n]
InfixC _ n _ -> [n]
ForallC _ _ c -> conNames c
patNames :: Pat -> [Name]
patNames p'' =
case p'' of
LitP _ -> []
VarP n -> [n]
TupP ps -> patNames `concatMap` ps
UnboxedTupP ps -> patNames `concatMap` ps
ConP _ ps -> patNames `concatMap` ps
InfixP p _ p' -> patNames `concatMap` [p,p']
UInfixP p _ p' -> patNames `concatMap` [p,p']
ParensP p -> patNames p
TildeP p -> patNames p
BangP p -> patNames p
AsP n p -> n:(patNames p)
WildP -> []
RecP _ fps -> patNames `concatMap` map snd fps
ListP ps -> patNames `concatMap` ps
SigP p _ -> patNames p
ViewP _ p -> patNames p