diff --git a/COPYRIGHT b/COPYRIGHT new file mode 100644 --- /dev/null +++ b/COPYRIGHT @@ -0,0 +1,61 @@ +The ChristmasTree package is (c) copyright 2008 +to the original authors and other contributors listed here. If you add +or modify code, please add your name here. + +Original authors: + Marcos Viera + Doaitse Swierstra + Eelco Lempsink + +---- +The GRead package is licensed under the terms of the GNU Lesser General Public +Licence (LGPL), which can be found in the file called LICENCE-LGPL, with +the following special exception: + + As a relaxation of clause 6 of the LGPL, the copyright holders of this + library give permission to use, copy, link, modify, and distribute, + binary-only object-code versions of an executable linked with the + original unmodified Library, without requiring the supply of any + mechanism to modify or replace the Library and relink (clauses 6a, + 6b, 6c, 6d, 6e), provided that all the other terms of clause 6 are + complied with. + +This software 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 +License for more details. + +---- +This software depends on library code by Daan Leijen, which +is distributed under the following license: + + The Modified BSD License + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions +are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + * 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. + + * Neither the names of the copyright holders, nor the names of its + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT +OWNER 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. + diff --git a/ChristmasTree.bib b/ChristmasTree.bib new file mode 100644 --- /dev/null +++ b/ChristmasTree.bib @@ -0,0 +1,13 @@ +@inproceedings{1411296, + author = {Marcos Viera and S. Doaitse Swierstra and Eelco Lempsink}, + title = {Haskell, do you read me?: constructing and composing efficient top-down parsers at runtime}, + booktitle = {Haskell '08: Proceedings of the first ACM SIGPLAN symposium on Haskell}, + year = {2008}, + isbn = {978-1-60558-064-7}, + pages = {63--74}, + location = {Victoria, BC, Canada}, + doi = {http://doi.acm.org/10.1145/1411286.1411296}, + publisher = {ACM}, + address = {New York, NY, USA}, + } + diff --git a/ChristmasTree.cabal b/ChristmasTree.cabal new file mode 100644 --- /dev/null +++ b/ChristmasTree.cabal @@ -0,0 +1,26 @@ +cabal-version: >=1.2 +build-type: Simple +name: ChristmasTree +version: 0.1 +license: LGPL +license-file: COPYRIGHT +maintainer: Marcos Viera +homepage: http://www.cs.uu.nl/wiki/bin/view/Center/TTTAS +description: Alternative approach of 'read' that composes grammars instead of parsers. It reads data in linear time, while the function 'read' has an exponential behavior in some cases of data types with infix operators. +synopsis: Changing Haskell's Read Implementation Such That by Mainpulating Abstract Syntax Trees it Reads Expressions Efficiently +category: Parsing +stability: Experimental +copyright: Universiteit Utrecht +build-depends: base, haskell98, template-haskell, containers, + fgl>=5.4, TTTAS, uulib +exposed-modules: Text.GRead, Text.GShow, + Text.GRead.Derive, Text.GRead.Grammar +other-modules: Text.GRead.Derive.BindingGroup, + Text.GRead.Transformations.GramTrafo, + Text.GRead.Transformations.Group, + Text.GRead.Transformations.LeftCorner, + Text.GRead.Transformations.LeftFact +extensions: Arrows, GADTs, TemplateHaskell +hs-source-dirs: src +extra-source-files: README, LICENSE-LGPL, ChristmasTree.bib +ghc-options: -Wall diff --git a/LICENSE-LGPL b/LICENSE-LGPL new file mode 100644 --- /dev/null +++ b/LICENSE-LGPL @@ -0,0 +1,507 @@ + GNU LESSER GENERAL PUBLIC LICENSE + Version 2.1, February 1999 + + Copyright (C) 1991, 1999 Free Software Foundation, Inc. + 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + +[This is the first released version of the Lesser GPL. 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+------------------------------------------- + + This is useful if you don't want (or can't) + modify system wide settings. + + ghc --make Setup.hs -o setup -package Cabal + ./setup configure --prefix=/foo + ./setup build + ./setup install --user + + The last command registers the package only for + the user. + + + +Optionally generating Haddock Documentation +------------------------------------------- + + Output generated in dist/doc/html + + ./setup haddock + diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,3 @@ + +import Distribution.Simple +main = defaultMain diff --git a/examples/Test.hs b/examples/Test.hs new file mode 100644 --- /dev/null +++ b/examples/Test.hs @@ -0,0 +1,127 @@ +module Test where + +import Text.GRead +import Language.TTTAS + +infixl 5 :<:, :+: +infixr 6 :>:, :*: + +data T1 = T1 :<: T1 + | T1 :>: T1 + | C1 + deriving (Read, Show) + +data T2 a = T2 a :+: T2 a + | a :*: T2 a + | C2 + deriving (Read, Show) + +data T3 = T3 T4 | C3 + deriving (Read, Show) +data T4 = T4 T3 | C4 + deriving (Read, Show) + + +_0 = Zero +_1 = Suc _0 +_2 = Suc _1 + + +instance Gram T1 where + grammar = DGrammar _0 envT1 + +envT1 :: Env DGram ((),T1) ((),T1) +envT1 = consD (nonts _0) Empty + where + nonts _T1 = DLNontDefs + [ ( DRef (_T1, 5) + , DPS [ dNont (_T1, 5) .#. dTerm ":<:" .#. + dNont (_T1, 6) .#. dEnd infixL ] + ) + , ( DRef (_T1, 6) + , DPS [ dNont (_T1, 7) .#. dTerm ":>:" .#. + dNont (_T1, 6) .#. dEnd infixR ] + ) + , ( DRef (_T1,10) + , DPS [ dTerm "C1" .#. dEnd (const C1) + , dTerm "(" .#. dNont (_T1,0) .#. + dTerm ")" .#. dEnd parenT ] + ) + ] + infixL e1 _ e2 = e2 :<: e1 + infixR e1 _ e2 = e2 :>: e1 + + +instance Gram a => Gram (T2 a) where + grammar = DGrammar _0 envT2 + +envT2 :: (Gram a) => Env DGram (((),a),T2 a) + (((),a),T2 a) +envT2 = consD (nonts _0 _1) $ + consG grammar Empty + where + nonts _T2 _A = DLNontDefs + [ ( DRef (_T2, 5) + , DPS [ dNont (_T2, 6) .#. dTerm ":+:" .#. + dNont (_T2, 6) .#. dEnd infixP ] + ) + , ( DRef (_T2, 6) + , DPS [ dNont (_A, 7) .#. dTerm ":*:" .#. + dNont (_T2, 7) .#. dEnd infixT ] + ) + , ( DRef (_T2,10) + , DPS [ dTerm "C2" .#. dEnd (const C2) + , dTerm "(" .#. dNont (_T2,0) .#. + dTerm ")" .#. dEnd parenT ] + ) + ] + infixP e1 _ e2 = e2 :+: e1 + infixT e1 _ e2 = e2 :*: e1 + +envT3T4 :: Env DGram (((), T4), T3) (((), T4), T3) +envT3T4 = consD (nonts3 _0 _1) $ + consD (nonts4 _1 _0) Empty + where + nonts3 _T3 _T4 = DLNontDefs + [ ( DRef (_T3,10) + , DPS [ dTerm "T3" .#. dNont (_T4,0) .#. + dEnd consT3 + , dTerm "C3" .#. dEnd (const C3) + , dTerm "(" .#. dNont (_T3,0) .#. + dTerm ")" .#. dEnd parenT + ] + ) + ] + nonts4 _T4 _T3 = DLNontDefs + [ ( DRef (_T4,10) + , DPS [ dTerm "T4" .#. dNont (_T3,0) .#. + dEnd consT4 + , dTerm "C4" .#. dEnd (const C4) + , dTerm "(" .#. dNont (_T4,0) .#. + dTerm ")" .#. dEnd parenT + ] + ) + ] + consT3 a = const (T3 a) + consT4 a = const (T4 a) + +instance Gram T3 where + grammar = DGrammar _0 envT3T4 + +instance Gram T4 where + grammar = DGrammar _1 envT3T4 + +read' :: (Gram a) => String -> a +read' input = case gread input of + Ok a -> a + Rep _ (m:_) -> error $ show m + +v1 = read' "C1 :>: C1 :>: C1" :: T1 +v2 = read' "C1 :<: C1 :<: C1" :: T1 +v3 = read' "C1 :>: C1 :<: C1 :>: C1" :: T1 +v4 = read' "(((((((((((((C1)))))))))))))" :: T1 +v5 = read' "(C1 :>: C1) :*: C2 :+: C2" :: T2 T1 +v6 = read' "T3 T4 T3 T4 C3" :: T3 +v7 = read' "T4 T3 T4 T3 T4 C3" :: T4 +v8 = read' "bla" :: T1 -- error + diff --git a/examples/Test2.hs b/examples/Test2.hs new file mode 100644 --- /dev/null +++ b/examples/Test2.hs @@ -0,0 +1,45 @@ +{-# OPTIONS -XScopedTypeVariables -XRankNTypes #-} +{-# LANGUAGE TemplateHaskell #-} + +module Test2 where + +import Text.GRead +import Text.GRead.Derive + +infixl 5 :<:, :+: +infixr 6 :>:, :*: + +data T1 = T1 :<: T1 + | T1 :>: T1 + | C1 + deriving (Read, Show) + +data T2 a = T2 a :+: T2 a + | a :*: T2 a + | C2 + deriving (Read, Show) + +data T3 = T3 T4 | C3 + deriving (Read, Show) +data T4 = T4 T3 | C4 + deriving (Read, Show) + +$(deriveGrammar ''T1) +$(deriveGrammar ''T2) +$(deriveGrammar ''T3) +$(deriveGrammar ''T4) + +read' :: (Gram a) => String -> a +read' input = case gread input of + Ok a -> a + Rep _ (m:_) -> error $ show m + +v1 = read' "C1 :>: C1 :>: C1" :: T1 +v2 = read' "C1 :<: C1 :<: C1" :: T1 +v3 = read' "C1 :>: C1 :<: C1 :>: C1" :: T1 +v4 = read' "(((((((((((((C1)))))))))))))" :: T1 +v5 = read' "(C1 :>: C1) :*: C2 :+: C2" :: T2 T1 +v6 = read' "T3 T4 T3 T4 C3" :: T3 +v7 = read' "T4 T3 T4 T3 T4 C3" :: T4 +v8 = read' "bla" :: T1 -- error + diff --git a/examples/TestDerive.hs b/examples/TestDerive.hs new file mode 100644 --- /dev/null +++ b/examples/TestDerive.hs @@ -0,0 +1,128 @@ +{-# OPTIONS -XScopedTypeVariables -XRank2Types #-} +{-# LANGUAGE TemplateHaskell #-} +module TestDerive where + +import Text.GRead +import Text.GRead.Derive + + +data T1 = T1 :<: T1 + | T1 :>: T1 + | C1 + deriving Show + +data T2 a = T2 a :+: T2 a + | a :*: T2 a + | C2 + deriving Show + +data T3 = T3 T4 | C3 + deriving Show + +data T4 = T4 T3 | C4 + deriving Show + +data T5 = T5 T6 | C5 + deriving Show + +data T6 = T6 T7 + deriving Show + +data T7 = T7 T5 + deriving Show + +data T8 = T8 (T2 T8) + | C8 + deriving Show + +data T9 = T9 (T2 T10) + | C9 + deriving Show + +data T10 = T10 T9 + deriving Show + +data T11 = T11 (T2 T11) + (T2 T12) + deriving Show + +data T12 = T12 T11 + deriving Show + +data T13 = T13 + deriving Show + +data T14 a b = T14 a b + deriving Show + +data T15 = T15 :-: T1 + | C15 + +data T16 = T1 :.: T16 + | C16 + + + +$(deriveGrammar ''T1) +$(deriveGrammar ''T2) +$(deriveGrammar ''T3) +$(deriveGrammar ''T4) +$(deriveGrammar ''T5) +$(deriveGrammar ''T6) +$(deriveGrammar ''T7) +$(deriveGrammar ''T8) +$(deriveGrammar ''T9) +$(deriveGrammar ''T10) +$(deriveGrammar ''T11) +$(deriveGrammar ''T12) +$(deriveGrammar ''T13) +$(deriveGrammar ''T14) +-- $(deriveGrammar ''T15) -- doesn't work +-- $(deriveGrammar ''T16) -- doesn't work + + +data BT a b c d e + = BT (BT a b c d e) (BT a b c d e) + | O_A a | O_B b | O_C c | O_D d | O_E e + | O_movl | O_movw | O_movb | O_movzbw | O_movzbl | O_movzwl + | O_movsbw | O_movsbl | O_movswl | O_pushl | O_popl + | O_pushfl | O_popfl | O_notl | O_notw | O_notb | O_sall | O_salw | O_salb + | O_sarl | O_sarw | O_sarb | O_shrl | O_shrw | O_shrb + | O_roll | O_rolw | O_rolb | O_rorl | O_rorw | O_rorb + | O_shldl | O_shrdl | O_addl | O_addw | O_addb + | O_adcl | O_subl | O_subw | O_subb | O_sbbl + | O_imull | O_imulw | O_imulb | O_mull | O_divl | O_divw | O_divb + | O_idivl | O_xorl | O_xorw | O_xorb | O_andl | O_andw | O_andb + | O_orl | O_orw | O_orb | O_incl | O_incw | O_incb + | O_decl | O_decw | O_decb | O_negl | O_negw | O_negb + | O_testl | O_testw | O_testb | O_leal | O_cmpl | O_cmpw | O_cmpb + | O_cmpsb | O_scasb | O_movsl | O_movsw | O_movsb + | O_stosl | O_stosw | O_stosb | O_leave | O_ret | O_call | O_jmp + | O_je | O_jne | O_jl | O_jle | O_jg | O_jge | O_js | O_jns + | O_jz | O_jnz | O_jc | O_jnc | O_jo | O_jno | O_ja | O_jae + | O_jb | O_jbe | O_jp | O_seta | O_setae | O_setb | O_setbe + | O_sete | O_setne | O_setl | O_setle | O_setg | O_setge + | O_setc | O_setcb | O_btl | O_btsl | O_btrl | O_btcl + | O_cld | O_cltd | O_cwtl | O_cbtw | O_rep | O_repz | O_repnz + | O_fild | O_fildl | O_fildll | O_fsubp | O_fsubr | O_fsubrp + | O_fsubrl | O_fsubrs | O_fsubs | O_fsubl | O_fsub + | O_faddp | O_fadds | O_faddl | O_fadd | O_fiaddl + | O_fmul | O_fmuls | O_fmull | O_fmulp + | O_fimull | O_fdiv | O_fdivp | O_fdivr | O_fdivrs | O_fdivrl | O_fdivrp + | O_fidivl | O_fidivrl | O_fdivl | O_fdivs + | O_fprem | O_fstp | O_fsts | O_fstps | O_fstl | O_fstpl | O_fstpt | O_fst + | O_fistl | O_fistpl | O_fistpll + | O_fld | O_flds | O_fldl | O_fldt | O_fldz | O_fld1 | O_fldl2e | O_fldln2 + | O_fchs | O_fsin | O_fcos | O_fptan | O_fsqrt | O_fpatan | O_fabs + | O_f2xm1 | O_fscale | O_fyl2x + | O_fucom | O_fucomp | O_fucompp + | O_fcomp | O_fcompp | O_fcoml | O_fcompl | O_ficompl + | O_fcoms | O_fcom | O_fcomps | O_fnstsw | O_fnstcw + | O_fldcw | O_frndint | O_fxch | O_sahf | O_nop + deriving (Show, Eq, Read) + +$(deriveGrammar ''BT) + + +res = gread "BT O_nop BT (O_B T10 C9) (O_E T14 C1 C3)" :: GReadResult (BT T1 T10 T11 T12 (T14 T1 T3)) + diff --git a/examples/TestShow.hs b/examples/TestShow.hs new file mode 100644 --- /dev/null +++ b/examples/TestShow.hs @@ -0,0 +1,62 @@ +{-# OPTIONS -XScopedTypeVariables -XRank2Types #-} +{-# LANGUAGE TemplateHaskell #-} + +module TestShow where + +import Text.GRead +import Text.GRead.Derive + +import Text.GShow + +import Language.Haskell.TH +import Language.Haskell.TH.Syntax + + +data T1 = T1 + deriving Show +$(deriveShow ''T1) + +s1 = gshow T1 + +data T2 a = T2 + +$(deriveShow ''T2) + +s2 = gshow (T2 :: (T2 T1)) + +data T3 a = T3 a + deriving Show + +$(deriveShow ''T3) + +s3 = gshow $ T3 T1 + +infixl 5 :<: +infixr 6 :>: + +data T4 a = T4 a :<: a + | T4 a :>: T4 a + | C4 + deriving Show + +data T5 = T5 + deriving Show + +$(deriveShow ''T4) +$(deriveShow ''T5) + +s41 = gshow (C4 :>: C4 :>: C4 :>: C4 :: T4 T5) +s42 = gshow ((C4 :>: C4) :>: C4 :: T4 T5) +s43 = gshow (C4 :>: (C4 :>: C4) :: T4 T5) +s44 = gshow (C4 :>: C4 :>: C4 :<: T5 :: T4 T5) +s45 = gshow (C4 :>: C4 :>: C4 :<: T5 :<: T5 :: T4 T5) + +$(deriveGrammar ''T4) +$(deriveGrammar ''T5) + +v41 = gread s41 :: GReadResult (T4 T5) +v42 = gread s42 :: GReadResult (T4 T5) +v43 = gread s43 :: GReadResult (T4 T5) +v44 = gread s44 :: GReadResult (T4 T5) +v45 = gread s45 :: GReadResult (T4 T5) + diff --git a/src/Text/GRead.hs b/src/Text/GRead.hs new file mode 100644 --- /dev/null +++ b/src/Text/GRead.hs @@ -0,0 +1,145 @@ +{-# OPTIONS -fglasgow-exts #-} + +{-| + Alternative approach of 'read' that composes grammars instead + of parsers. Grammars describing the data types are composed + dynamically, removing possible left-recursion and combining + common prefixes of alternatives. + + The function 'gread' defined here is able to handle the + associativities defined for infix operators. + + The function 'gread' reads data in linear time, while the + function 'read' has an exponential behavior in some cases + of data types with infix operators. + + Non uniform data types are not supported, because they + generate infinite grammars. + + The library is documented in the paper: /Haskell, do you read me?: constructing and composing efficient top-down parsers at runtime/ + + Bibtex entry: + + For more documentation see the TTTAS webpage: . + -} + +module Text.GRead ( + -- * Grammar Description + module Text.GRead.Grammar, + + -- * Reading Functions + gread, + + -- * Types + GReadMsg, GReadResult(..) + + ) where + +import Language.TTTAS +import Text.GRead.Grammar +import Text.GRead.Transformations.LeftFact +import Text.GRead.Transformations.LeftCorner +import Text.GRead.Transformations.Group +import UU.Parsing hiding (Symbol,parse,Ok) +import qualified UU.Parsing as UU +import List (findIndex) + + +-- | Type of error repair messages. +type GReadMsg = Message Token (Maybe Token) + + +-- | Type of 'gread' results. +data GReadResult a = Ok a + | Rep a [GReadMsg] + deriving Show + + +-- | The 'gread' reads input from a string, which must be +-- completely consumed by the input process. +-- Returns @Ok value@ on a successful parse. +-- Otherwise returns @Rep value msgs@, where the @value@ +-- results of parsing a repaired input. The list @msgs@ +-- contains the \"corrections\" done to the input. +-- +-- For example, a 'read'-like implementation can be: +-- +-- > read :: (Gram a) => String -> a +-- > read input = case gread input of +-- > Ok a -> a +-- > Rep _ (m:_) -> error $ show m + + +gread :: (Gram a) => String -> GReadResult a +gread = ( parse . compile + . leftfactoring . leftcorner + . group ) grammar + + + +-- COMPILE -------------------------------------------------------------------- + +newtype Const f a s = C {unC :: f a} + +compile :: forall a . Grammar a -> Parser Token a +compile (Grammar (start :: Ref a env) rules) + = unC (lookupEnv start result) + where result = + mapEnv + (\ (PS ps) -> C (foldr1 (<|>) [ comp p | p <- ps])) + rules + comp :: forall t . Prod t env -> Parser Token t + comp (End x) = pLow x + comp (Seq (Term t) ss) + = (flip ($)) <$> pSym t <*> comp ss + comp (Seq (Nont n) ss) + = (flip ($)) <$> unC (lookupEnv n result) + <*> comp ss + +mapEnv :: (forall a . f a s -> g a s) + -> Env f s env -> Env g s env +mapEnv _ Empty = Empty +mapEnv f (Ext r v) = Ext (mapEnv f r) (f v) + + +instance Show Token where + show (Keyw s) = s + show Open = "(" + show Close = ")" + +instance UU.Symbol Token where + deleteCost _ = 5 + + +-- PARSE ---------------------------------------------------------------------- + +parse :: Parser Token a -> String -> GReadResult a +parse p input = case rparse p input of + (a,[] ) -> Ok a + (a,msgs) -> Rep a msgs + + +rparse :: Parser Token a -> String -> (a, [GReadMsg]) +rparse p input = let ((Pair a _),msgs) = eval (UU.parse p (tokenize input)) + in (a,msgs) + where eval :: Steps a Token (Maybe Token) -> (a, [GReadMsg]) + eval (OkVal v r) = let (a,msgs) = v `seq` (eval r) + in (v a,msgs) + eval (UU.Ok r) = eval r + eval (Cost _ r) = eval r + eval (StRepair _ msg r) = let (v,msgs) = eval r + in (v,msg:msgs) + eval (Best _ r _) = eval r + eval (NoMoreSteps v ) = (v,[]) + + tokenize [] = [] + tokenize ('(':xs) = Open : (tokenize xs) + tokenize (')':xs) = Close : (tokenize xs) + tokenize (' ':xs) = tokenize xs + tokenize l = case findIndex endTok l of + Just i -> let (ky,rs) = splitAt i l + in Keyw ky : (tokenize rs) + Nothing -> [Keyw l] + + endTok t = t == ')' || t == ' ' || t == '(' + diff --git a/src/Text/GRead/Derive.hs b/src/Text/GRead/Derive.hs new file mode 100644 --- /dev/null +++ b/src/Text/GRead/Derive.hs @@ -0,0 +1,355 @@ +{-# LANGUAGE TemplateHaskell #-} + +{-| + Automatically derive 'Text.GRead.Gram' instances for data types. + + /Note!/ This is not a complete implementation and will not work for all datatypes. + + Unsupported are + + * Multiple type arguments + + * Tuple, Function, List types + + * All primitive types (also when used in user defined types!) + + Use with care. + -} +module Text.GRead.Derive (deriveGrammar, deriveSimpleGrammar) where + +import Text.GRead.Grammar +import Language.TTTAS + +import Text.GRead.Derive.BindingGroup + +import Data.List (nub, foldl', foldl1') +import Data.Foldable (foldr') +import Data.Map (Map) +import qualified Data.Map as Map (insertWith, empty, toList) +import Control.Monad (foldM) + +import Language.Haskell.TH +import Language.Haskell.TH.Syntax + +{-| + Derive a 'Text.GRead.Gram' instance. This is a Template Haskell function. Usage example: + +@ +data T1 = C1 | C2 | C3 + +$(deriveGrammar ''T1) +@ +-} +deriveGrammar :: Name -> Q [Dec] +deriveGrammar name = do + bindingGroup <- getBindingGroup name + deriveGrammar' name bindingGroup + + +{-| + Simpler version of 'deriveGrammar' that doesn't do binding group + calculations. Use this for large types without cyclic references to other + types. + + For example, if you want to derive the 'HDYRM.Gram' for 'T3' and 'T4' + below, you will need the normal 'deriveGrammar'. + +@ +data T3 = T3 T4 | C3 +data T4 = T4 T3 | C4 +@ +-} +deriveSimpleGrammar :: Name -> Q [Dec] +deriveSimpleGrammar name = deriveGrammar' name [] + +deriveGrammar' :: Name -> BindingGroup -> Q [Dec] +deriveGrammar' name bindingGroup = do + (UserD _ args cs) <- getUserType name + body <- mkBody name cs bindingGroup + return [InstanceD (mkContext cs) (mkInstanceType name args) body] + +mkContext :: [Con] -> Cxt +mkContext = map (AppT (ConT ''Gram)) . uniqueVars . consArgsTypes + +mkInstanceType :: Name -> [Name] -> Type +mkInstanceType name = AppT (ConT ''Gram) . foldl1' AppT . (:) (ConT name) . map VarT + +consArgsTypes :: [Con] -> [Type] +consArgsTypes = concatMap consArgs + where + consArgs :: Con -> [Type] + consArgs (NormalC _ args) = map snd args + consArgs (InfixC argl _ argr) = [snd argl, snd argr] + +uniqueVars :: [Type] -> [Type] +uniqueVars = nub . filter isVarT . unrollApps + where + unrollApps :: [Type] -> [Type] + unrollApps [] = [] + unrollApps (a@(AppT _ _):ts) = unrollApp a ++ unrollApps ts + unrollApps (other:ts) = other : unrollApps ts + +isVarT :: Type -> Bool +isVarT (VarT _) = True +isVarT _ = False + + +mkBody :: Name -> [Con] -> BindingGroup -> Q [Dec] +mkBody top cs bindingGroup = do + let bindingGroup' | bindingGroup == [] = [(top, [])] + | otherwise = bindingGroup + neededInstances = concatMap snd bindingGroup' + strongEdges <- mapM (calculateStrongEdges neededInstances) bindingGroup' + instances <- mapM (createInstances neededInstances strongEdges) bindingGroup' + let instances' = concat instances + nontsInstance = mkNontsInstance strongEdges bindingGroup' (instanceExps instances') + topPat = map varP (instanceNames instances') + env = appsE $ (lamE topPat nontsInstance) : (linkRefs (length instances')) + [d| grammar = DGrammar Zero $(sigE env (envSignature cs (instanceTypes instances'))) |] + where + instanceNames = map (fst . fst) + instanceTypes = map (snd . fst) + instanceExps = map snd + + +-- Only edges that are not in the binding group +calculateStrongEdges :: [(Name, [[Type]])] -> (Name, [(Name, [[Type]])]) -> Q (Name, [Type]) +calculateStrongEdges needed (typeName, edges) = do + (UserD _ _ cs) <- getUserType typeName + return $ (typeName, mkNonBGEdges typeName (map fst needed) (bindingGroupEdges typeName needed) cs) + where + bindingGroupEdges typeName needed = maybe [] concat $ Prelude.lookup typeName needed + + mkNonBGEdges self done before = filter (not . already done before self) . consArgsTypes + + already :: [Name] -> [Type] -> Name -> Type -> Bool + already done before self (VarT _) = True + already done before self c@(ConT name) = elem c before + || elem name done + || name == self + already done before self a@(AppT _ _) = elem a before + || elem (conName a) done + || (conName a) == self + where conName = (\(ConT name) -> name) . head . unrollApp + -- TODO Incomplete: TupleT, ListT, etc... + +getEdges :: Name -> [(Name, [Type])] -> [Type] +getEdges name = maybe [] id . Prelude.lookup name + + +-- The non-terminal rules, wrapped in lambda expression to select the grammars from this closed group +mkNontsInstance :: [(Name, [Type])] -> BindingGroup -> [ExpQ] -> Q Exp +mkNontsInstance strongEdges bindingGroup instances = do + nontsTypes <- mapM (mkNontsType strongEdges) bindingGroup + appsE $ (lamE (mkNontsPat nontsTypes bindingGroup) (foldr' appE [|Empty|] instances)) + : (mkNonts strongEdges bindingGroup) + where + mkNonts edges = map (mkGrammarPart edges) + mkNontsPat types = map (\(t, v) -> sigP v (do return t)) . zip types . nontsPatVars + nontsPatVars = map (varP . type2Nonts . fst) + +envSignature :: [Con] -> [Type] -> Q Type +envSignature cs types = if null (consVars cs) + then envSignature' + else forallT (consVars cs) (return $ mkContext cs) envSignature' + where + consVars :: [Con] -> [Name] + consVars = map (\(VarT n) -> n) . uniqueVars . consArgsTypes + + envSignature' :: Q Type + envSignature' = foldl1' appT [conT ''Env, conT ''DGram, tupleTypes types, tupleTypes types] + + -- Make a nested tuple of the types + tupleTypes :: [Type] -> Q Type + tupleTypes = foldr' ((\x xs -> appT (appT (tupleT 2) xs) x)) (conT ''()) . map return + + +-- If there are args, see if we need instances (from needed) +-- Create all needed instances +-- Also, if there's still a var, create a consG for that +-- Return a list of tuples of the name of an instance and the instance itself +createInstances :: [(Name, [[Type]])] -> [(Name, [Type])] -> (Name, [(Name, [[Type]])]) -> Q [((Name, Type), ExpQ)] +createInstances needed strongEdges (typeName, edges) = do + (UserD _ args cs) <- getUserType typeName + let instancesNeeded = maybe [map VarT args] id $ Prelude.lookup typeName needed + return $ mkInstances instancesNeeded + ++ mkArgInstances instancesNeeded + ++ mkNonBGInstances typeName strongEdges + where + mkConsG :: Type -> ((Name, Type), ExpQ) + mkConsG typ = ((instName typeName typ, typ), [|consG grammar|]) + + mkInstances = map (createInstance (typeName, edges) (getEdges typeName strongEdges)) + mkArgInstances = map mkConsG . filter isVarT . concat + + mkNonBGInstances typeName = map mkConsG . getEdges typeName + + +createInstance :: (Name, [(Name, [[Type]])]) -> [Type] -> [Type] -> ((Name, Type), ExpQ) +createInstance (typeName, edges) strongEdges inst = ((iName, iType), [|consD $(appsE $ (varE $ type2Nonts typeName) : (selfArgs ++ strongEdgeArgs ++ nonBGStrongEdges)) |]) + where iName = nameArgs (type2TopRef typeName) inst + iType = foldl1' AppT (ConT typeName : inst) + selfArgs = (varE iName) : (map (varE . instName typeName) inst) + strongEdgeArgs = concatMap refEdge edges + nonBGStrongEdges = map (varE . instName typeName) strongEdges + +instName :: Name -> Type -> Name +instName top (VarT n) = var2TopRef top n +instName _ (ConT n) = type2TopRef n +instName _ app@(AppT _ _) = app2TopRef $ unrollApp app + + +mkNontsType :: [(Name, [Type])] -> (Name, [(Name, [[Type]])]) -> Q Type +mkNontsType strongEdges (typeName, edges) = do + (UserD _ args _) <- getUserType typeName + let envName = mkName "env" + env = VarT envName + ref = ConT ''Ref + argsType = map VarT args + topType = foldl' AppT (ConT typeName) argsType + resultType = AppT (AppT (ConT ''DLNontDefs) topType) env + refTo = (topType : argsType) ++ concatMap edgeType edges ++ getEdges typeName strongEdges + refs = map (\r -> AppT (AppT ref r) env) refTo + nontsType = foldr' (\r rs -> AppT (AppT ArrowT r) rs) resultType refs + return $ ForallT (envName:args) [] nontsType + +edgeType :: (Name, [[Type]]) -> [Type] +edgeType (con, argss) = map (foldl' AppT (ConT con)) argss + +mkGrammarPart :: [(Name, [Type])] -> (Name, [(Name, [[Type]])]) -> Q Exp +mkGrammarPart strongEdges (typeName, edges) = do + (UserD _ args cons) <- getUserType typeName + let selfArgsNames = (type2Ref typeName) : (map (var2Ref typeName) args) + strongEdgeNames = concatMap nameEdge edges + -- Strong edges that are not part of the binding group + nonBGStrongEdgeNames = map getTypeName $ getEdges typeName strongEdges + lamE (map varP (selfArgsNames ++ strongEdgeNames ++ nonBGStrongEdgeNames)) (conProds cons typeName) + where + getTypeName (ConT name) = type2Ref name + getTypeName a@(AppT _ _) = app2Ref (unrollApp a) + -- TODO Incomplete: TupleT, ListT, etc... + + +refEdge :: (Name, [[Type]]) -> [ExpQ] +refEdge (con, argss) = map (varE . nameArgs baseName) argss + where baseName = type2TopRef con + +nameEdge :: (Name, [[Type]]) -> [Name] +nameEdge (con, argss) = map (nameArgs baseName) argss + where baseName = type2Ref con + +-- TODO: Extend this for 'AppT' and clean up +nameArgs :: Name -> [Type] -> Name +nameArgs baseName [] = baseName +nameArgs baseName ((ConT name):types) = nameArgs (mkName $ nameBase baseName ++ "'" ++ nameBase name) types +nameArgs baseName ((VarT name):types) = nameArgs (mkName $ nameBase baseName ++ "'" ++ nameBase name) types + +-- TODO: Simplification, not finished, doesn't support AppT at the moment +getNeededInstances :: (Name, [[Type]]) -> [(Name, [Type])] +getNeededInstances (top, argss) = concatMap (\args -> (top,args): map (\arg -> (typeName arg, [])) args) argss + where typeName (ConT n) = n -- Break with a pattern match failure + +linkRefs :: Int -> [ExpQ] +linkRefs x = linkRefs' (x-1) [[|Zero|]] -- Minus one is for the top type, works always + where linkRefs' 0 done = reverse done + linkRefs' x' l@(last:_) = linkRefs' (x' - 1) ((appE [|Suc|] last):l) + +type PrecProd = Map Int [ExpQ] + +conProds :: [Con] -> Name -> Q Exp +conProds cs top = do + prods <- foldM (insertCon top) Map.empty cs + -- Add the parenthesis production + prods' <- insertCon' 10 (parensProd top) prods + let prodList = map (\(prec, nonts) -> + tupE [ [|DRef ($(varE $ type2Ref top), prec)|] + , appE [|DPS|] (listE nonts) + ] + ) + (Map.toList prods') + appE [|DLNontDefs|] $ listE prodList + +parensProd :: Name -> Q Exp +parensProd top = [| dTerm "(" .#. (dNont ($(varE $ type2Ref top), 0)) .#. dTerm ")" .#. dEnd parenT |] + +getTypeRef :: Name -> Int -> StrictType -> Q Exp +getTypeRef top p (_,t) = [| dNont ($(varE (refTo top t)), p) |] + where refTo top' (VarT n) = var2Ref top' n + refTo _ (ConT n) = type2Ref n + refTo top' app@(AppT _ _) = appOrType2Ref top' $ unrollApp app + appOrType2Ref cur app@((ConT con):_) | cur == con = type2Ref cur -- TODO: Is this always true? + | otherwise = app2Ref app + -- TODO Incomplete? + +-- TODO: first argument doesn't have to be a con! +app2Ref :: [Type] -> Name +app2Ref ((ConT con):args) = nameArgs (type2Ref con) args + +app2TopRef :: [Type] -> Name +app2TopRef ((ConT con):args) = nameArgs (type2TopRef con) args + +-- TODO: Nice for readability, but should be cleaned up +type2Ref :: Name -> Name +type2Ref = type2Ref' "_r_" + +type2Ref' :: String -> Name -> Name +type2Ref' prefix t = mkName $ prefix ++ nameBase t + +var2Ref :: Name -> Name -> Name +var2Ref = var2Ref' "_r_" + +var2Ref' :: String -> Name -> Name -> Name +var2Ref' prefix t v = mkName $ prefix ++ nameBase t ++ "_" ++ nameBase v + +type2Nonts :: Name -> Name +type2Nonts = type2Ref' "_nonts_" + +var2TopRef :: Name -> Name -> Name +var2TopRef = var2Ref' "_t_" + +type2TopRef :: Name -> Name +type2TopRef = type2Ref' "_t_" + +nameStringE :: Name -> Q Exp +nameStringE = stringE . nameBase + +insertCon :: Name -> PrecProd -> Con -> Q PrecProd +insertCon top pp (NormalC name args) = do + insertCon' 10 (foldr1 appE ( + [ [| (.#.) $ dTerm $(nameStringE name) |] ] ++ + ( map (appE [|(.#.)|] . (getTypeRef top 0)) args ) ++ + [ [| dEnd $(consExp name (length args)) |] ] + )) pp + +insertCon top pp (InfixC argl name argr) = do + (prec, precl, precr) <- getPrec name + let refl = getTypeRef top precl argl + refr = getTypeRef top precr argr + insertCon' prec (infixProd refl (nameBase name) refr (conE name)) pp + +insertCon _ _ _ = undefined -- TODO + + +infixProd :: ExpQ -> String -> ExpQ -> ExpQ -> Q Exp +infixProd argl term argr op = + [| $argl .#. dTerm term .#. $argr .#. + dEnd (\e1 _ e2 -> $(appsE [op, [|e2|], [|e1|]])) + |] + +getPrec :: Name -> Q (Int, Int, Int) +getPrec name = do + (DataConI _ _ _ (Fixity f fd)) <- reify name + return (f, (f + fLeft fd), (f + fRight fd)) + where + fLeft InfixL = 0 + fLeft InfixR = 1 + fRight InfixR = 0 + fRight InfixL = 1 + +insertCon' :: Int -> ExpQ -> PrecProd -> Q PrecProd +insertCon' i e pp = return $ Map.insertWith (flip (++)) i [e] pp + +consExp :: Name -> Int -> Q Exp +consExp name times = do + let names = map (\x -> mkName $ "arg" ++ show x) [1..times] + lamE (map varP names ++ [wildP]) (appsE $ (conE name):(map varE (reverse names))) diff --git a/src/Text/GRead/Derive/BindingGroup.hs b/src/Text/GRead/Derive/BindingGroup.hs new file mode 100644 --- /dev/null +++ b/src/Text/GRead/Derive/BindingGroup.hs @@ -0,0 +1,242 @@ +{-# LANGUAGE TemplateHaskell #-} + +{-| + Module used internally by the "Derive" module for binding group calculation. + -} + +module Text.GRead.Derive.BindingGroup ( + -- * Binding group + BindingGroup + , getBindingGroup + , showBindingGroup + -- * Template Haskell helpers + , UserType(..) + , getUserType + , unrollApp + ) where + +import Language.Haskell.TH.Syntax + +import Data.List (nub, intersect) +import Data.Maybe (fromJust) +import qualified Data.Map as M + +import qualified Data.Graph.Inductive.Graph as G +import qualified Data.Graph.Inductive.Tree as G +import qualified Data.Graph.Inductive.Query.BFS as G +import qualified Data.Graph.Inductive.NodeMap as G + +import Control.Monad (foldM) + +-- | Uniform representation of 'data' and 'newtype' +data UserType = UserD Name [Name] [Con] + +-- | Edges can be Strong (direct) or Weak (through variable) +data EdgeType = Strong [Type] | Weak [Type] deriving (Show, Eq) + +-- | Graph of our type dependencies +type TypeGraph = G.Gr Name EdgeType +type TypeContext = G.Context Name EdgeType + +-- | The next edge, parent and type +type NextEdge = (EdgeType, G.Node) + +-- | Map for looking up vars +type VarMap = M.Map Name Type + +-- This will be our 'inherited' attributes, as we walk the tree of types +-- type InheritState = (NextEdge, VarMap, TypeGraph) +data InheritState = IS { nextEdge :: NextEdge + , varMap :: VarMap + , typeGraph :: TypeGraph + , bindings :: M.Map Name VarMap -- Also used as a loop-check + -- Actually synthesized, but here to enable tail recursion + , nodeMap :: G.NodeMap Name + , contexts :: [TypeContext] + } + +type SynthesizedState = (G.NodeMap Name, [TypeContext]) + +-- | Mapping from types to the list of types (with specific constructor instantiations, the '[[Type]]') in the same binding group. +type BindingGroup = [(Name, [(Name, [[Type]])])] + +startState :: Name -> InheritState +startState firstType = + let (firstNode, firstNodemap) = G.mkNode G.new firstType + firstContext = ([], fst firstNode, snd firstNode, []) + in IS { nextEdge = (Strong [], fst firstNode) + , varMap = M.empty + , bindings = M.singleton firstType M.empty + , typeGraph = firstContext G.& G.empty + , nodeMap = firstNodemap + , contexts = [firstContext] + } + +returnState :: InheritState -> Q SynthesizedState +returnState state = return (nodeMap state, contexts state) + +-- Show functions for console debugging +showBindingGroup :: Name -> Q Exp +showBindingGroup name = do + bgroup <- getBindingGroup name + let bgroup' = map show bgroup + [|bgroup'|] + +showTypeGraph :: Name -> Q Exp +showTypeGraph name = do + tgraph <- getTypeGraph name + let tgraph' = show tgraph + [|tgraph'|] + +-- | Find cyclic type dependencies (binding groups) +getBindingGroup :: Name -> Q BindingGroup +getBindingGroup name = do + typegr <- getTypeGraph name + -- Broken in 'labeled' pieces to make it better readable + let loopClosers = G.pre typegr 0 + loops = map (\x -> G.esp 0 x typegr) loopClosers + bindingGroup = nub $ concat loops + -- Create the bindings first, we'll look them up when constructing the final binding group. + bindings = typeBindings typegr bindingGroup + return $ map (\x -> (typeName typegr x, outgoingBindings typegr x bindings)) bindingGroup + -- TODO Do we need to take into account the case that the 'top' type takes arguments and add a variable binding? + +typeName :: TypeGraph -> G.Node -> Name +typeName typegr node = fromJust $ G.lab typegr node + +typeBindings :: TypeGraph -> [G.Node] -> M.Map G.Node [[Type]] +typeBindings typegr bindingGroup = M.fromList $ map (\x -> (x, bindings x)) bindingGroup + where bindings x = nub $ map (getBindings . thd) $ G.inn typegr x + +-- Only strong edges +outgoingBindings :: TypeGraph -> G.Node -> M.Map G.Node [[Type]] -> [(Name, [[Type]])] +outgoingBindings typegr node bindings = map (\x -> (typeName typegr x, maybe (error $ show x) id $ M.lookup x bindings)) edgesOut + where edgesOut = filter ((/=) node) $ intersect (M.keys bindings) $ map getTargetNode $ filter strongEdge $ nub $ G.out typegr node + strongEdge (_, _, Strong _) = True + strongEdge _ = False + getTargetNode (_, n, _) = n + +-- TODO This suggests a better (wrapping) type +getBindings :: EdgeType -> [Type] +getBindings (Strong types) = types +getBindings (Weak types) = types + +-- Build the typegraph +getTypeGraph :: Name -> Q TypeGraph +getTypeGraph name = do + utype@(UserD uname _ _) <- getUserType name + (_, contexts') <- extendGraphType (startState uname) utype + return $ mkGraph' contexts' + +mkGraph' :: (Eq a, Eq b) => [G.Context a b] -> G.Gr a b +mkGraph' contexts = + let nodes = nub $ map G.labNode' contexts + edges = concatMap (\x -> (G.inn' x) ++ (G.out' x)) contexts -- Don't nub, do that where it's really needed + in G.mkGraph nodes edges + +-- | Get a unified type for 'data' and 'newtype' +getUserType :: Name -> Q UserType +getUserType name = do + info <- reify name + case info of + TyConI d -> case d of + (DataD _ uname args cs _) -> return $ UserD uname args cs + (NewtypeD _ uname args c _) -> return $ UserD uname args [c] + _ -> scopeError + _ -> scopeError + where scopeError = error $ "Can only be used on algebraic datatypes (which " ++ (show name) ++ " isn't)" + +extendGraphType :: InheritState -> UserType -> Q SynthesizedState +extendGraphType state (UserD _ _ cons) = do + startState <- returnState state + foldM (\(nodeMap', contexts') utype -> + extendGraph (state { contexts = contexts', nodeMap = nodeMap' }) utype) + startState + (getCtx cons) + +-- Context of a data type, based on the arguments in it's constructors. Not the context of a graph. +getCtx :: [Con] -> [Type] +getCtx [] = [] +getCtx ((NormalC _ args) :cs) = (map snd args) ++ (getCtx cs) +getCtx ((InfixC argl _ argr) :cs) = (snd argl) : ((snd argr) : (getCtx cs)) +getCtx ((RecC _ args) :cs) = (map thd args) ++ (getCtx cs) +-- Not exhaustive: missing ForallC + +thd :: (a, b, c) -> c +thd (_, _, c) = c + +extendGraph :: InheritState -> Type -> Q SynthesizedState +extendGraph state nextType = case nextType of + VarT varname -> extendGraphVar state varname + ConT conname -> extendGraphCon state conname + app@(AppT _ _) -> extendGraphApp state app + _ -> error $ "Couldn't match: " ++ (show nextType) + +extendGraphVar :: InheritState -> Name -> Q SynthesizedState +extendGraphVar state name = do + case M.lookup name (varMap state) of + Just (VarT _) -> returnState state + Nothing -> returnState state -- From toplevel + -- Follow the var, but make the link weak + Just vartype -> extendGraph (state { nextEdge = (Weak [], snd $ nextEdge state) }) vartype + +extendGraphCon :: InheritState -> Name -> Q SynthesizedState +extendGraphCon state name = do + newState <- insNode state name + utype@(UserD _ args _) <- getUserType name + case M.lookup name (bindings state) of + Just oldVarMap | oldVarMap == varMap state || args == [] -> returnState newState + _ -> do + extendGraphType newState { bindings = M.insert name (varMap state) (bindings state) } utype + +insNode :: InheritState -> Name -> Q InheritState +insNode state name = do + (UserD _ args _) <- getUserType name + let ((nodeNr, _), newNodeMap) = G.mkNode (nodeMap state) name + (edgeType, parent) = nextEdge state + nextEdge' = (mkNextEdgeType edgeType args (varMap state), parent) + newContexts = ([nextEdge'], nodeNr, name, []) : (contexts state) + return $ state { nextEdge = (Strong [], nodeNr) + , typeGraph = mkGraph' newContexts + , contexts = newContexts + , nodeMap = newNodeMap + } + +mkNextEdgeType :: EdgeType -> [Name] -> VarMap -> EdgeType +mkNextEdgeType (Strong _) args vm = Strong $ mkNextEdgeType' args vm [] +mkNextEdgeType (Weak _) args vm = Weak $ mkNextEdgeType' args vm [] + +mkNextEdgeType' :: [Name] -> VarMap -> [Type] -> [Type] +mkNextEdgeType' [] _ types = types +mkNextEdgeType' (a:args) vm types = case M.lookup a vm of + Nothing -> mkNextEdgeType' args vm ((VarT a):types) + Just t -> mkNextEdgeType' args vm (t :types) + +extendGraphApp :: InheritState -> Type -> Q SynthesizedState +extendGraphApp state app = do + let (app':appargs) = replaceVars (unrollApp app) (varMap state) + varmap' <- extendVarMap app' appargs (varMap state) + extendGraph (state { varMap = varmap' }) app' + +extendVarMap :: Type -> [Type] -> VarMap -> Q VarMap +extendVarMap utype appargs varmap = + case utype of + ConT uname -> do + (UserD _ args _) <- getUserType uname + return $ M.union (M.fromList $ zip args appargs) varmap + _ -> return varmap + +-- | Get the types of a type application +unrollApp :: Type -> [Type] +unrollApp app = unrollApp' app [] + where unrollApp' :: Type -> [Type] -> [Type] + unrollApp' (AppT sub@(AppT _ _) arg) args = unrollApp' sub (arg:args) + unrollApp' (AppT top arg) args = top:(arg:args) + -- Not exhaustive: missing ArrowT, ContT, ForallT, ListT, ... + +replaceVars :: [Type] -> VarMap -> [Type] +replaceVars [] _ = [] +replaceVars (t@(VarT v):ts) vm = case M.lookup v vm of + Nothing -> t : replaceVars ts vm + Just t' -> t' : replaceVars ts vm +replaceVars (t:ts) vm = t : replaceVars ts vm diff --git a/src/Text/GRead/Grammar.hs b/src/Text/GRead/Grammar.hs new file mode 100644 --- /dev/null +++ b/src/Text/GRead/Grammar.hs @@ -0,0 +1,212 @@ +{-# OPTIONS -fglasgow-exts #-} + +{- | + + Representation of Data Type Grammars. + +-} +module Text.GRead.Grammar ( + -- * Class Gram + Gram(..), + + -- * Typed Grammar Representations for Data Types + + -- ** Types + DGrammar(..), DGram(..), DRef(..), DLNontDefs(..), + DProductions(..), DProd(..), DSymbol(..), + + -- ** Smart Constructors + ( .#. ), consG, consD, dNont, dTerm, dEnd, parenT, + + -- * Typed Grammar Representations + + -- ** Types + Grammar(..), Productions(..), Prod(..), + Symbol(..), Token(..), + + -- ** Smart Constructors + ext, ( .*. ), + + -- ** Utils + matchSym, append + ) where + +import Language.TTTAS (Env(..), Ref(..), Equal(..), match) + +-- | +-- +-- Class of data types with typed grammar representation. It has to be +-- instantiated in order to use the function 'Text.GRead.gread'. +-- +-- Instances can be derived automatically using the functions defined +-- in the module "Text.GRead.Derive". +-- +-- For example, given the declarations +-- +-- > infixl 5 :<: +-- > infixr 6 :>:, :*: +-- > +-- > data T1 = T1 :<: T1 +-- > | T1 :>: T1 +-- > | C1 +-- > +-- > data T2 a = a :*: T2 a +-- > | C2 +-- +-- the instances of 'Gram' can be +-- +-- > _0 = Zero +-- > _1 = Suc _0 +-- > +-- > instance Gram T1 where +-- > grammar = DGrammar _0 envT1 +-- > +-- > envT1 :: Env DGram ((),T1) ((),T1) +-- > envT1 = consD (nonts _0) Empty +-- > where +-- > nonts _T1 = DLNontDefs +-- > [ ( DRef (_T1, 5) +-- > , DPS [ dNont (_T1, 5) .#. dTerm ":<:" .#. +-- > dNont (_T1, 6) .#. dEnd infixL ] +-- > ) +-- > , ( DRef (_T1, 6) +-- > , DPS [ dNont (_T1, 7) .#. dTerm ":>:" .#. +-- > dNont (_T1, 6) .#. dEnd infixR ] +-- > ) +-- > , ( DRef (_T1,10) +-- > , DPS [ dTerm "C1" .#. dEnd (const C1) +-- > , dTerm "(" .#. dNont (_T1,0) .#. +-- > dTerm ")" .#. dEnd parenT ] +-- > ) +-- > ] +-- > infixL e1 _ e2 = e2 :<: e1 +-- > infixR e1 _ e2 = e2 :>: e1 +-- > +-- > instance Gram a => Gram (T2 a) where +-- > grammar = DGrammar _0 envT2 +-- > +-- > envT2 :: (Gram a) => Env DGram (((),a),T2 a) +-- > (((),a),T2 a) +-- > envT2 = consD (nonts _0 _1) $ +-- > consG grammar Empty +-- > where +-- > nonts _T2 _A = DLNontDefs +-- > [ ( DRef (_T2, 6) +-- > , DPS [ dNont (_A, 7) .#. dTerm ":*:" .#. +-- > dNont (_T2, 7) .#. dEnd infixT ] +-- > ) +-- > , ( DRef (_T2,10) +-- > , DPS [ dTerm "C2" .#. dEnd (const C2) +-- > , dTerm "(" .#. dNont (_T2,0) .#. +-- > dTerm ")" .#. dEnd parenT ] +-- > ) +-- > ] +-- > infixP e1 _ e2 = e2 :+: e1 +-- > infixT e1 _ e2 = e2 :*: e1 +-- +-- In case of mutually recursive datatypes, their definitions have +-- to be tupled together into a single environment. + +class Gram a where + -- | The function 'grammar' returns the grammar representation of + -- the data type. + grammar :: DGrammar a + +-- | Data type describing grammatical structures of data types, +-- including information about precedences. The type @DGrammar a@ +-- describes the grammar of the data type @a@. +data DGrammar a + -- | A grammar consists of an environment ('Env') with the + -- defined non-terminals and a reference ('Ref') to the + -- /main non-terminal/ in the environment. + = forall env. DGrammar (Ref a env) + (Env DGram env env) + +data DGram a env = DGD (DLNontDefs a env) + | DGG (DGrammar a) +newtype DRef a env = DRef (Ref a env, Int) +newtype DLNontDefs a env + = DLNontDefs [(DRef a env, DProductions a env)] +newtype DProductions a env + = DPS { unDPS :: [DProd a env] } + +data DProd a env where + DSeq :: DSymbol b env -> DProd (b->a) env + -> DProd a env + DEnd :: a -> DProd a env + +data DSymbol a env where + DNont :: DRef a env -> DSymbol a env + DTerm :: Token -> DSymbol Token env + +infixr 5 .#. + +( .#. ) :: DSymbol b env -> DProd (b -> a) env -> DProd a env +( .#. ) = DSeq + +consG :: DGrammar a -> Env DGram use def' -> Env DGram use (def', a) +consG g es = Ext es (DGG g) + +consD :: DLNontDefs a env -> Env DGram env def' -> Env DGram env (def', a) +consD g es = Ext es (DGD g) + +dNont :: (Ref a env, Int) -> DSymbol a env +dNont nt = DNont (DRef nt) + +dTerm :: [Char] -> DSymbol Token env +dTerm t | t == "(" = DTerm Open + | t == ")" = DTerm Close + | otherwise = DTerm (Keyw t) + +dEnd :: a -> DProd a env +dEnd f = DEnd f + +parenT :: t -> t1 -> t2 -> t1 +parenT _ e _ = e + + + +data Grammar a + = forall env . Grammar (Ref a env) + (Env Productions env env) + +newtype Productions a env + = PS {unPS :: [Prod a env]} + +data Prod a env where + Seq :: Symbol b env -> Prod ( b -> a) env + -> Prod a env + End :: a -> Prod a env + +data Symbol a env where + Nont :: Ref a env -> Symbol a env + Term :: Token -> Symbol Token env + +data Token = Keyw String + | Open + | Close + deriving (Ord, Eq) + + +infixr 5 `ext` , .*. + +ext :: Env Productions env def' -> [Prod a env] + -> Env Productions env (def', a) +ext g prods = Ext g (PS prods) + +( .*. ) :: Symbol b env -> Prod (b -> a) env -> Prod a env +( .*. ) = Seq + +matchSym :: Symbol a env -> Symbol b env + -> Maybe (Equal a b) +matchSym (Nont x) (Nont y) = match x y +matchSym (Term x) (Term y) | x == y = Just Eq +matchSym _ _ = Nothing + + +append :: (a -> b -> c) -> Prod a env -> Symbol b env + -> Prod c env +append g (End f ) s = Seq s (End (g f)) +append g (Seq t ts ) s + = Seq t (append (\b c d -> g (b d) c) ts s) + diff --git a/src/Text/GRead/Transformations/GramTrafo.hs b/src/Text/GRead/Transformations/GramTrafo.hs new file mode 100644 --- /dev/null +++ b/src/Text/GRead/Transformations/GramTrafo.hs @@ -0,0 +1,52 @@ +{-# OPTIONS -fglasgow-exts #-} + +module Text.GRead.Transformations.GramTrafo where + +import Language.TTTAS +import Text.GRead.Grammar + +newtype MapA_X env a env' + = MapA_X (forall x. Symbol x env -> Maybe (Ref (x -> a) env')) + +emptyMap :: MapA_X env a env' +emptyMap = MapA_X (const Nothing) + +extendMap :: Symbol x env -> MapA_X env a env' + -> MapA_X env a (env',x->a) +extendMap x (MapA_X m) + = MapA_X (\s -> case matchSym s x of + Just Eq -> Just Zero + Nothing -> fmap Suc (m s) + ) + + +type GramTrafo env a = Trafo (MapA_X env a) Productions + + +initMap :: GramTrafo env a s c d + -> Trafo Unit Productions s c d +initMap (Trafo st) + = Trafo (\_ -> case st emptyMap of + TrafoE _ f -> TrafoE Unit f + ) + +newNontR :: forall x env s a + . Symbol x env + -> GramTrafo env a s (Productions (x->a) s) (Ref (x->a) s) +newNontR x = Trafo $ \m -> extEnv (extendMap x m) + + +newtype Mapping old new + = Mapping (Env Ref new old) + +map2trans :: Mapping env s -> T env s +map2trans (Mapping env) + = T (\r -> (lookupEnv r env)) + +mapProd :: T env1 env2 -> Prod a env1 -> Prod a env2 +mapProd _ (End x) = End x +mapProd t (Seq (Nont x) r) = Seq (Nont (unT t x)) + (mapProd t r) +mapProd t (Seq (Term x) r) = Seq (Term x) + (mapProd t r) + diff --git a/src/Text/GRead/Transformations/Group.hs b/src/Text/GRead/Transformations/Group.hs new file mode 100644 --- /dev/null +++ b/src/Text/GRead/Transformations/Group.hs @@ -0,0 +1,96 @@ +{-# OPTIONS -fglasgow-exts -XArrows #-} + +module Text.GRead.Transformations.Group where + +import Language.TTTAS +import Text.GRead.Grammar +import Control.Arrow + + +newtype DT env1 env2 + = DT { unDT :: forall a . DRef a env1 -> Ref a env2 } + +mapDP2Prod :: DT env1 env2 -> DProd a env1 + -> Prod a env2 + +mapDP2Prod _ (DEnd x) = End x +mapDP2Prod t (DSeq (DNont x) r) + = Seq (Nont (unDT t x)) + (mapDP2Prod t r) +mapDP2Prod t (DSeq (DTerm x) r) + = Seq (Term x) + (mapDP2Prod t r) + + +type GTrafo = Trafo Unit Productions + +dp2prod :: DProd a env -> GTrafo s (DT env s) (Prod a s) +dp2prod p = arr ( \env2s -> mapDP2Prod env2s p ) + +ld2nt :: (DRef a env, DProductions a env) + -> GTrafo s (DT env s) (DRef a s) + +ld2nt (DRef (rnt,i),DPS lp) + = proc env2s -> + do ps <- sequenceA (map dp2prod lp) -< env2s + (PS nl) <- mkNxtLev -< env2s + r <- newSRef -< PS $ nl++ps + returnA -< DRef (r,i) + where + mkNxtLev = arr $ \t -> PS $ + (if (i<10) + then [Seq (Nont $ unDT t $ + DRef (rnt,i+1)) + (End id)] + else []) + +newtype ListDR a s = ListDR { unListDR :: [DRef a s] } + +newtype DMapping o n = DMapping { unDMapping :: Env ListDR n o } + +dmap2trans :: DMapping env s -> DT env s +dmap2trans (DMapping env) + = DT (\ (DRef (r,i)) + -> case (lookupEnv r env) of + ListDR rs -> (plookup i rs)) + +plookup :: Int -> [DRef a s] -> Ref a s +plookup _ [] = error "Wrong Grammar!!" +plookup i ((DRef (r,p)):drs) + | i <= p = r + | otherwise = plookup i drs + + + +group :: DGrammar a -> Grammar a +group gram + = let trafo = proc x -> + do (ListDR rs) <- (gGrammar gram) -< x + returnA -< plookup 0 rs + in case runTrafo trafo Unit undefined of + Result _ r grm -> Grammar r grm + +gGrammar :: DGrammar a + -> GTrafo s t (ListDR a s) +gGrammar (DGrammar r gram) = proc _ -> + mdo let env_s = dmap2trans menv_s + menv_s <- gDGrams gram -< env_s + returnA -< lookupEnv r (unDMapping menv_s) + + +gDGrams :: Env DGram env env' + -> GTrafo s (DT env s) (DMapping env' s) + +gDGrams Empty = arr (const (DMapping Empty)) + +gDGrams (Ext ps (DGG gram)) + = proc env_s -> + do refs <- gGrammar gram -< env_s + ms <- gDGrams ps -< env_s + returnA -< DMapping $ Ext (unDMapping ms) refs +gDGrams (Ext ps (DGD (DLNontDefs nonts))) + = proc env_s -> + do r <- sequenceA (map ld2nt nonts) -< env_s + ms <- gDGrams ps -< env_s + returnA -< DMapping $ Ext (unDMapping ms) (ListDR r) + diff --git a/src/Text/GRead/Transformations/LeftCorner.hs b/src/Text/GRead/Transformations/LeftCorner.hs new file mode 100644 --- /dev/null +++ b/src/Text/GRead/Transformations/LeftCorner.hs @@ -0,0 +1,109 @@ +{-# OPTIONS -fglasgow-exts -XArrows #-} + +module Text.GRead.Transformations.LeftCorner (leftcorner) where + +import Language.TTTAS +import Text.GRead.Grammar +import Text.GRead.Transformations.GramTrafo +import Control.Arrow + + +leftcorner :: forall a . Grammar a -> Grammar a +leftcorner (Grammar start productions) + = case runTrafo (lctrafo productions) Unit () of + Result _ (T tt) gram -> + Grammar (tt start) gram + +lctrafo :: Env Productions env env + -> Trafo Unit Productions s () (T env s) +lctrafo productions = proc _ -> + mdo let tenv_s = map2trans menv_s + menv_s <- (rules1 productions productions) -< tenv_s + returnA -< tenv_s + + +rules1 :: Env Productions env env + -> Env Productions env env' + -> Trafo Unit Productions s (T env s) + (Mapping env' s) +rules1 _ Empty + = proc _ -> + returnA -< Mapping Empty + +rules1 productions (Ext ps (PS prods)) + = proc tenv_s -> + do p <- app_rule1 productions prods -< tenv_s + r <- newSRef -< p + Mapping e <- rules1 productions ps -< tenv_s + returnA -< Mapping (Ext e r) + +app_rule1 :: forall env a s. Env Productions env env + -> [Prod a env] + -> Trafo Unit Productions s (T env s) (Productions a s) +app_rule1 productions prods = initMap + ( proc tenv_s -> + do pss <- sequenceA (map (rule1 productions) prods) -< tenv_s + returnA -< PS (concatMap unPS pss) + ) + +rule1 :: Env Productions env env -> Prod a env + -> GramTrafo env a s (T env s) (Productions a s) +rule1 gram (Seq x beta) + = proc tenv_s -> + do insert gram x -< (tenv_s, mapProd tenv_s beta) + + +rule2 :: Env Productions env env + -> Symbol x env + -> GramTrafo env a s (T env s, Ref (x -> a) s) + (Productions a s) +rule2 _ (Term a) + = proc (_, a_x) -> + do returnA -< PS [rule2a a a_x] +rule2 gram (Nont b) + = case lookupEnv b gram of + PS ps -> proc (tenv_s, a_x) -> + do pss <- sequenceA + (map (rule2b gram) ps) -< (tenv_s, a_x) + returnA -< PS (concatMap unPS pss) + + +rule2a :: Token -> Ref (Token -> a) s -> Prod a s +rule2a a refA_a + = Term a .*. Nont refA_a .*. End ($) + +rule2b :: Env Productions env env + -> Prod b env + -> GramTrafo env a s (T env s, Ref (b -> a) s) + (Productions a s) +rule2b gram (Seq x beta) + = proc (tenv_s, a_b) -> + do insert gram x -< (tenv_s, append (flip (.)) + (mapProd tenv_s beta) + (Nont a_b)) + +insert :: forall env s a x + . Env Productions env env + -> Symbol x env + -> GramTrafo env a s (T env s, Prod (x->a) s) + (Productions a s) +insert gram x = + Trafo ( + \(MapA_X m) -> case m x of + Just r -> extendA_X (MapA_X m) r + Nothing -> let Trafo step = insertNewA_X + in step (MapA_X m) + ) + where + insertNewA_X = proc (tenv_s,p) -> + do r <- newNontR x -< PS [p] + rule2 gram x -< (tenv_s,r) + + +extendA_X :: m env2-> Ref (x->a) env2-> TrafoE m Productions s env2 (t, Prod (x->a) s) (Productions a env) +extendA_X m r = fmap (const $ PS []) $ + updateSRef m r (\(_,p) (PS ps) -> PS (p:ps)) + + + + diff --git a/src/Text/GRead/Transformations/LeftFact.hs b/src/Text/GRead/Transformations/LeftFact.hs new file mode 100644 --- /dev/null +++ b/src/Text/GRead/Transformations/LeftFact.hs @@ -0,0 +1,148 @@ +{-# OPTIONS -fglasgow-exts -XArrows #-} + +module Text.GRead.Transformations.LeftFact (leftfactoring) where + +import Language.TTTAS +import Text.GRead.Grammar +import Text.GRead.Transformations.GramTrafo +import Control.Arrow +import Data.Maybe + + + +--list of repeated symbols (with hidden type) +data AnySym env = forall x. AnySym (Symbol x env) + +newtype BT env s = BT (Bool, T env s) + +-- The 'leftfactoring' function makes a feed-back loop to apply the +-- transformation to the Grammar. +-- If the transformation has produced new nonterminals (repeated initial +-- symbols have been found) the 'leftfactoring' function is called again. +leftfactoring :: forall a. Grammar a -> Grammar a +leftfactoring (Grammar start productions) + = case runTrafo (lftrafo productions) Unit () of + Result _ (BT (b,T tt)) gram -> + let g = Grammar (tt start) gram + in if b then leftfactoring g + else g + +lftrafo :: Env Productions env env + -> Trafo Unit Productions s () (BT env s) +lftrafo productions = proc _ -> + mdo let tenv_s = map2trans menv_s + (b,menv_s) <- (rules productions) -< tenv_s + returnA -< BT (b,tenv_s) + + +-- The function 'rules' is defined by induction over the original Grammar. +-- Applies the "transformation rule" for each nonterminal (and +-- its corresponding productions) of the Grammar. +-- First of all, the list of "repeated initial symbols" in the productions +-- of a nonterminal is found. +-- Having this list, the rule is applied to the productions. +-- The nonterminal is added to the new Grammar, with the productions +-- generated by the rule. +-- The output of the Trafo is compound by a boolean indicating if repeated +-- symbols were found, and the Mapping from the positions in the new Grammar +-- for each nonterminal of the old Grammar. +rules :: Env Productions env env' + -> Trafo Unit Productions s (T env s) (Bool,(Mapping env' s)) +rules Empty + = proc _ -> + returnA -< (False, Mapping Empty) + +rules (Ext ps (PS prods)) = + let rep = getrepeated prods + in proc tenv_s -> + do p <- app_rule rep prods -< tenv_s + r <- newSRef -< p + (bs,Mapping e) <- rules ps -< tenv_s + returnA -< ((length rep > 0) || bs, Mapping (Ext e r)) + +app_rule :: forall env a s. [AnySym env] + -> [Prod a env] + -> Trafo Unit Productions s (T env s) (Productions a s) +app_rule rep prods = initMap + ( proc tenv_s -> + do pss <- sequenceA (map (rule rep) prods) -< tenv_s + returnA -< PS (concatMap unPS pss) + ) + +-- If the first symbol of the production is in the list of "repeated +-- initial symbols", the transformation generated by 'rinstert' +-- is called with input the rest of the production. So, a new nonterminal +-- A_Rest_X is generated (if necessary) and the rest (beta) of the production +-- is stored as a production of it. +-- In other case the production (with its references mapped to the +-- to the new Grammar) is returned. +rule :: [AnySym env] -> Prod a env + -> GramTrafo env a s (T env s) (Productions a s) +rule _ (End a) = proc env2s -> + do returnA -< PS [ mapProd env2s (End a) ] + +rule rep (Seq x beta) + | x `iselem` rep = proc env2s -> + do rinsert x -< (env2s, mapProd env2s beta) + | otherwise = proc env2s -> + do returnA -< PS [ mapProd env2s (Seq x beta) ] + + +-- Insertion of a new production into one "rest" nonterminal. +-- If the symbol 'x' is in the MapA_X the nonterminal was already +-- added, so we obtain the reference of the nonterminal and add the new +-- production. +-- Otherwise, we have to create the new nonterminal (newNontR x). +rinsert :: forall env s a x. Symbol x env + -> GramTrafo env a s (T env s, Prod (x->a) s) (Productions a s) +rinsert x = + Trafo ( + \(MapA_X m) -> case m x of + Nothing -> case proc (env2s,p) -> + do r <- newNontR x -< PS [p] + addprod x -< (env2s,r) + of Trafo step -> step (MapA_X m) + Just r -> TrafoE (MapA_X m) + (\(_,p) t e -> + ( PS [] + , t + , updateEnv (\(PS ps) + -> PS (p:ps)) + r e + ) + ) + ) + + +addprod :: Symbol x env -> GramTrafo env a s (T env s, Ref (x -> a) s) + (Productions a s) +addprod (Term x) = proc (_, a__x) -> + do returnA -< PS [ Term x .*. Nont a__x .*. End ($)] +addprod (Nont r) = proc (env2s,a__x) -> + do returnA -< PS [ Nont (unT env2s r) .*. Nont a__x + .*. End ($)] + + +-- Get the list of symbols that are repeated as "first symbol" in the list +-- of productions. +getrepeated :: [Prod a env] -> [AnySym env] +getrepeated prods = repeated $ mapMaybe head' prods + where head' (End _ ) = Nothing + head' (Seq x _) = Just (AnySym x) + repeated [] = [] + repeated (ax@(AnySym x):xs) + | x `iselem` xs = ax : repeated (filter (noteqAny ax) xs) + | otherwise = repeated xs + + noteqAny (AnySym x) (AnySym y) = (aux $ matchSym x y) + +aux :: Maybe (Equal a b) -> Bool +aux (Just Eq) = False +aux Nothing = True + +iselem :: Symbol t env -> [AnySym env] -> Bool +iselem _ [] = False +iselem x ((AnySym y):ys) = case (matchSym x y) of + (Just Eq) -> True + Nothing -> iselem x ys + diff --git a/src/Text/GShow.hs b/src/Text/GShow.hs new file mode 100644 --- /dev/null +++ b/src/Text/GShow.hs @@ -0,0 +1,122 @@ +{-# LANGUAGE TemplateHaskell #-} + +module Text.GShow ( GShow(..), deriveShow, app_prec ) where + +import Text.GRead +import Language.TTTAS + +import Language.Haskell.TH +import Language.Haskell.TH.Syntax + +import Data.List (nub, foldl1') + +class GShow a where + gshow :: a -> String + gshowsPrec :: Int -> a -> ShowS + +app_prec = 10 :: Int + + +data ADInfo = ADInfo [Name] [Con] + +deriveShow :: Name -> Q [Dec] +deriveShow name = do + (ADInfo args cons) <- getInfo name + let targs = map VarT args + ctx = map (AppT (ConT ''GShow)) (nub $ filterVars $ unrollApps $ mkContext cons) + typ = AppT (ConT ''GShow) (foldl1' AppT $ (ConT name):targs) + + gs <- [d| gshow a = gshowsPrec 0 a "" |] + let clcons = map deriveShowCon cons + gsps <- funD (mkName "gshowsPrec") clcons + return [ InstanceD ctx typ (gsps:gs) ] + + + +mkContext :: [Con] -> Cxt +mkContext [] = [] +mkContext ((NormalC _ args) :cs) = (map snd args) ++ (mkContext cs) +mkContext ((InfixC argl _ argr) :cs) = (snd argl) : ((snd argr) : (mkContext cs)) + +filterVars :: Cxt -> Cxt +filterVars [] = [] +filterVars (v@(VarT _):vs) = v : filterVars vs +filterVars (_:vs) = filterVars vs + +unrollApps :: [Type] -> [Type] +unrollApps [] = [] +unrollApps (a@(AppT _ _):ts) = unrollApp a ++ unrollApps ts +unrollApps (other:ts) = other : unrollApps ts + +unrollApp :: Type -> [Type] +unrollApp app = unrollApp' app [] + where unrollApp' :: Type -> [Type] -> [Type] + unrollApp' (AppT sub@(AppT _ _) arg) args = unrollApp' sub (arg:args) + unrollApp' (AppT top arg) args = top:(arg:args) + + +deriveShowCon :: Con -> Q Clause + +deriveShowCon (NormalC name types) = do + names <- mapM (const $ newName "x") types + let pat = conP name (map varP names) + shows = map ((appE fgshowp) . varE) names + clause [varP (mkName "d"), pat] (bdy shows) [] + where + bdy s = normalB (appE (appE fshowParen cond) (str s)) + fshowParen = varE $ mkName "showParen" + cond = infixE (Just $ varE $ mkName "d") + (varE $ mkName ">") + (Just $ varE $ mkName "app_prec") + str s = infixE (Just (appE (varE $ mkName "showString") cons)) + (varE $ mkName ".") (Just $ conc s) + cons = litE $ StringL (nameBase name ++ " ") + fgshowp = appE (varE $ mkName "gshowsPrec") (varE $ mkName "app_prec") + conc [] = [| id |] + conc (s:[]) = [| $(s) |] + conc (s:rs) = [| $(s) . $(conc rs)|] + + +deriveShowCon (InfixC _ name _) = do + f <- getPrec name + clause [varP (mkName "d"), pat] (bdy f) [] + where + l = mkName "l" + r = mkName "r" + pat = infixP (varP l) name (varP r) + bdy (f,fl,fr) = normalB (appE (appE fshowParen (cond f)) (str fl fr)) + fshowParen = varE $ mkName "showParen" + cond f = infixE (Just $ varE $ mkName "d") + (varE $ mkName ">") + (Just [| f |]) + + fshowsPrec d n = appE (appE (varE $ mkName "gshowsPrec") [| d |]) n + strl fl = appE (appE (varE $ mkName ".") (fshowsPrec fl (varE l))) + (appE (varE $ mkName "showString") + (litE $ StringL (' ' : nameBase name ++ " "))) + str fl fr = appE (appE (varE $ mkName ".") (strl fl)) + (fshowsPrec fr (varE r)) + +getPrec :: Name -> Q (Int, Int, Int) +getPrec name = do + (DataConI _ _ _ (Fixity f fd)) <- reify name + return (f, (f + fLeft fd), (f + fRight fd)) + where + fLeft InfixL = 0 + fLeft InfixR = 1 + fRight InfixR = 0 + fRight InfixL = 1 + + + +getInfo :: Name -> Q ADInfo +getInfo name = do + info <- reify name + case info of + TyConI d -> case d of + (DataD _ _ args cs _) -> return $ ADInfo args cs + (NewtypeD _ _ args c _) -> return $ ADInfo args [c] + _ -> scopeError + _ -> scopeError + where scopeError = error $ "Can only be used on algebraic datatypes (which " ++ (show name) ++ " isn't)" +