{-# LANGUAGE CPP #-} {-# LANGUAGE ScopedTypeVariables #-} {-| The parser doesn't know about operators and parses everything as normal function application. This module contains the functions that parses the operators properly. For a stand-alone implementation of this see @src\/prototyping\/mixfix\/old@. It also contains the function that puts parenthesis back given the precedence of the context. -} module Agda.Syntax.Concrete.Operators ( parseApplication , parseModuleApplication , parseLHS , parsePattern , parsePatternSyn ) where import Control.DeepSeq import Control.Applicative import Control.Monad import Data.Either (partitionEithers) import Data.Function import Data.List import Data.Maybe import Data.Map (Map) import qualified Data.Map as Map import Data.Set (Set) import qualified Data.Set as Set import Data.Traversable (traverse) import qualified Data.Traversable as Trav import Agda.Syntax.Concrete.Pretty () import Agda.Syntax.Common hiding (Arg, Dom, NamedArg) import qualified Agda.Syntax.Common as Common import Agda.Syntax.Concrete hiding (appView) import Agda.Syntax.Concrete.Operators.Parser import qualified Agda.Syntax.Abstract.Name as A import Agda.Syntax.Position import Agda.Syntax.Fixity import Agda.Syntax.Notation import Agda.Syntax.Scope.Base import Agda.Syntax.Scope.Monad import Agda.TypeChecking.Monad.Base (typeError, TypeError(..), LHSOrPatSyn(..)) import qualified Agda.TypeChecking.Monad.Benchmark as Bench import Agda.TypeChecking.Monad.State (getScope) import Agda.TypeChecking.Monad.Options import Agda.Utils.Either import Agda.Utils.ReadP #if MIN_VERSION_base(4,8,0) import Agda.Utils.List hiding ( uncons ) #else import Agda.Utils.List #endif #include "undefined.h" import Agda.Utils.Impossible --------------------------------------------------------------------------- -- * Billing --------------------------------------------------------------------------- -- | Bills the operator parser. billToParser :: ScopeM a -> ScopeM a billToParser = Bench.billTo [Bench.Parsing, Bench.Operators] --------------------------------------------------------------------------- -- * Building the parser --------------------------------------------------------------------------- type FlatScope = Map QName [AbstractName] -- | Compute all defined names in scope and their fixities/notations. -- Note that overloaded names (constructors) can have several -- fixities/notations. Then we 'mergeNotations'. (See issue 1194.) getDefinedNames :: [KindOfName] -> FlatScope -> [[NewNotation]] getDefinedNames kinds names = [ mergeNotations $ map (\d -> namesToNotation x (A.qnameName $ anameName d)) ds | (x, ds) <- Map.toList names , any ((`elem` kinds) . anameKind) ds , not (null ds) -- Andreas, 2013-03-21 see Issue 822 -- Names can have different kinds, i.e., 'defined' and 'constructor'. -- We need to consider all names that have *any* matching kind, -- not only those whose first appearing kind is matching. ] -- | Compute all names (first component) and operators/notations -- (second component) in scope. localNames :: FlatScope -> ScopeM ([QName], [NewNotation]) localNames flat = do let defs = getDefinedNames allKindsOfNames flat locals <- notShadowedLocals <$> getLocalVars -- Note: Debug printout aligned with the one in buildParsers. reportSLn "scope.operators" 50 $ unlines [ "flat = " ++ show flat , "defs = " ++ show defs , "locals= " ++ show locals ] let localNots = map localOp locals localNames = Set.fromList $ map notaName localNots otherNots = filter (\n -> not (Set.member (notaName n) localNames)) (concat defs) return $ split $ localNots ++ otherNots where localOp (x, y) = namesToNotation (QName x) y split ops = partitionEithers $ concatMap opOrNot ops opOrNot n = Left (notaName n) : if null (notation n) then [] else [Right n] -- | Data structure filled in by @buildParsers@. -- The top-level parser @pTop@ is of primary interest, -- but @pArgs@ is used to convert module application -- from concrete to abstract syntax. data Parsers e = Parsers { pTop :: ReadP e e , pApp :: ReadP e e , pArgs :: ReadP e [NamedArg e] , pNonfix :: ReadP e e , pAtom :: ReadP e e } data UseBoundNames = UseBoundNames | DontUseBoundNames {-| Builds parser for operator applications from all the operators and function symbols in scope. When parsing a pattern we use 'DontUseBoundNames'. The effect is that operator parts (that are not constructor parts) can be used as atomic names in the pattern (so they can be rebound). See test/succeed/OpBind.agda for an example. To avoid problems with operators of the same precedence but different associativity we decide (completely arbitrary) to fix the precedences of operators with the same given precedence in the following order (from loosest to hardest): - non-associative - left associative - right associative - prefix - postfix This has the effect that if you mix operators with the same precedence but different associativity the parser won't complain. One could argue that this is a Bad Thing, but since it's not trivial to implement the check it will stay this way until people start complaining about it. -} buildParsers :: forall e. IsExpr e => Range -> FlatScope -> UseBoundNames -> ScopeM (Parsers e) buildParsers r flat use = do (names, ops) <- localNames flat let cons = getDefinedNames [ConName, PatternSynName] flat reportSLn "scope.operators" 50 $ unlines [ "names = " ++ show names , "ops = " ++ show ops , "cons = " ++ show cons ] let conparts = Set.fromList $ concatMap notationNames $ concat cons opsparts = Set.fromList $ concatMap notationNames ops allParts = Set.union conparts opsparts connames = Set.fromList $ map (notaName . head) cons (non, fix) = partition nonfix ops set = Set.fromList names isAtom x = case use of UseBoundNames -> not (Set.member x allParts) || Set.member x set DontUseBoundNames -> not (Set.member x conparts) || Set.member x connames -- If string is a part of notation, it cannot be used as an identifier, -- unless it is also used as an identifier. See issue 307. let chain = foldr ( $ ) return $ Data.Function.fix $ \p -> Parsers { pTop = chain (pApp p) (concatMap (mkP (pTop p)) (order fix)) , pApp = appP (pNonfix p) (pArgs p) , pArgs = argsP (pNonfix p) , pNonfix = chain (pAtom p) (map (nonfixP . opP (pTop p)) non) , pAtom = atomP isAtom } where level :: NewNotation -> Integer level = fixityLevel . notaFixity nonfix, isprefix, ispostfix :: NewNotation -> Bool nonfix = (== NonfixNotation) . notationKind . notation isprefix = (== PrefixNotation) . notationKind . notation ispostfix = (== PostfixNotation) . notationKind . notation isinfix :: Associativity -> NewNotation -> Bool isinfix ass syn = notationKind (notation syn) == InfixNotation && fixityAssoc (notaFixity syn) == ass -- | Group operators by precedence level order :: [NewNotation] -> [[NewNotation]] order = groupBy ((==) `on` level) . sortBy (compare `on` level) -- | Each element of the returned list takes the parser for an -- expression of higher precedence as parameter. mkP :: ReadP e e -> [NewNotation] -> [ReadP e e -> ReadP e e] mkP p0 ops = case concat [infx, inlfx, inrfx, prefx, postfx] of [] -> [id] fs -> fs where inlfx = fixP infixlP (isinfix LeftAssoc) inrfx = fixP infixrP (isinfix RightAssoc) infx = fixP infixP (isinfix NonAssoc) prefx = fixP prefixP isprefix postfx = fixP postfixP ispostfix fixP :: (ReadP e (NewNotation,Range,[e]) -> ReadP e e -> ReadP e e) -> (NewNotation -> Bool) -> [ReadP e e -> ReadP e e] fixP f g = case filter g ops of [] -> [] ops -> [ f $ choice $ map (opP p0) ops ] --------------------------------------------------------------------------- -- * Helpers for pattern and lhs parsing --------------------------------------------------------------------------- -- | View a pattern @p@ as a list @p0 .. pn@ where @p0@ is the identifier -- (in most cases a constructor). -- -- Pattern needs to be parsed already (operators resolved). patternAppView :: Pattern -> [NamedArg Pattern] patternAppView p = case p of AppP p arg -> patternAppView p ++ [arg] OpAppP _ x _ ps -> defaultNamedArg (IdentP x) : ps ParenP _ p -> patternAppView p RawAppP _ _ -> __IMPOSSIBLE__ _ -> [ defaultNamedArg p ] --------------------------------------------------------------------------- -- * Parse functions --------------------------------------------------------------------------- -- | Returns the list of possible parses. parsePat :: ReadP Pattern Pattern -> Pattern -> [Pattern] parsePat prs p = case p of AppP p (Common.Arg info q) -> fullParen' <$> (AppP <$> parsePat prs p <*> (Common.Arg info <$> traverse (parsePat prs) q)) RawAppP _ ps -> fullParen' <$> (parsePat prs =<< parse prs ps) OpAppP r d ns ps -> fullParen' . OpAppP r d ns <$> (mapM . traverse . traverse) (parsePat prs) ps HiddenP _ _ -> fail "bad hidden argument" InstanceP _ _ -> fail "bad instance argument" AsP r x p -> AsP r x <$> parsePat prs p DotP r e -> return $ DotP r e ParenP r p -> fullParen' <$> parsePat prs p WildP _ -> return p AbsurdP _ -> return p LitP _ -> return p QuoteP _ -> return p IdentP _ -> return p {- Implement parsing of copattern left hand sides, e.g. record Tree (A : Set) : Set where field label : A child : Bool -> Tree A -- corecursive function defined by copattern matching alternate : {A : Set}(a b : A) -> Tree A -- shallow copatterns label (alternate a b) = a child (alternate a b) True = alternate b a -- deep copatterns: label (child (alternate a b) False) = b child (child (alternate a b) False) True = alternate a b child (child (alternate a b) False) False = alternate a b Delivers an infinite tree a b b a a a a b b b b b b b b ... Each lhs is a pattern tree with a distinct path of destructors ("child", "label") from the root to the defined symbol ("alternate"). All branches besides this distinct path are patterns. Syntax.Concrete.LHSCore represents a lhs - the destructor path - the side patterns - the defined function symbol - the applied patterns -} type ParseLHS = Either Pattern (Name, LHSCore) parseLHS' :: LHSOrPatSyn -> Maybe Name -> Pattern -> ScopeM ParseLHS parseLHS' lhsOrPatSyn top p = do let ms = qualifierModules $ patternQNames p flat <- flattenScope ms <$> getScope parsers <- buildParsers (getRange p) flat DontUseBoundNames let patP = pTop parsers let cons = getNames [ConName, PatternSynName] flat let flds = getNames [FldName] flat case [ res | p' <- force $ parsePat patP p , res <- validPattern (PatternCheckConfig top cons flds) p' ] of [(p,lhs)] -> return lhs [] -> typeError $ NoParseForLHS lhsOrPatSyn p rs -> typeError $ AmbiguousParseForLHS lhsOrPatSyn p $ map (fullParen . fst) rs where getNames kinds flat = map (notaName . head) $ getDefinedNames kinds flat -- validPattern returns an empty or singleton list (morally a Maybe) validPattern :: PatternCheckConfig -> Pattern -> [(Pattern, ParseLHS)] validPattern conf p = case (classifyPattern conf p, top) of (Just r@(Left _), Nothing) -> [(p, r)] -- expect pattern (Just r@(Right _), Just{}) -> [(p, r)] -- expect lhs _ -> [] -- | Name sets for classifying a pattern. data PatternCheckConfig = PatternCheckConfig { topName :: Maybe Name -- ^ name of defined symbol , conNames :: [QName] -- ^ valid constructor names , fldNames :: [QName] -- ^ valid field names } -- | Returns zero or one classified patterns. classifyPattern :: PatternCheckConfig -> Pattern -> Maybe ParseLHS classifyPattern conf p = case patternAppView p of -- case @f ps@ Common.Arg _ (Named _ (IdentP x@(QName f))) : ps | Just f == topName conf -> do guard $ all validPat ps return $ Right (f, LHSHead f ps) -- case @d ps@ Common.Arg _ (Named _ (IdentP x)) : ps | x `elem` fldNames conf -> do -- ps0 :: [NamedArg ParseLHS] ps0 <- mapM classPat ps let (ps1, rest) = span (isLeft . namedArg) ps0 (p2, ps3) <- uncons rest -- when (null rest): no field pattern or def pattern found guard $ all (isLeft . namedArg) ps3 let (f, lhs) = fromR p2 (ps', _:ps'') = splitAt (length ps1) ps return $ Right (f, LHSProj x ps' lhs ps'') -- case: ordinary pattern _ -> do guard $ validConPattern (conNames conf) p return $ Left p where -- allNames = conNames conf ++ fldNames conf validPat = validConPattern (conNames conf) . namedArg classPat :: NamedArg Pattern -> Maybe (NamedArg ParseLHS) classPat = Trav.mapM (Trav.mapM (classifyPattern conf)) fromR :: NamedArg (Either a (b, c)) -> (b, NamedArg c) fromR (Common.Arg info (Named n (Right (b, c)))) = (b, Common.Arg info (Named n c)) fromR (Common.Arg info (Named n (Left a ))) = __IMPOSSIBLE__ -- | Parses a left-hand side, and makes sure that it defined the expected name. -- TODO: check the arities of constructors. There is a possible ambiguity with -- postfix constructors: -- Assume _ * is a constructor. Then 'true *' can be parsed as either the -- intended _* applied to true, or as true applied to a variable *. If we -- check arities this problem won't appear. parseLHS :: Name -> Pattern -> ScopeM LHSCore parseLHS top p = billToParser $ do res <- parseLHS' IsLHS (Just top) p case res of Right (f, lhs) -> return lhs _ -> typeError $ NoParseForLHS IsLHS p -- | Parses a pattern. -- TODO: check the arities of constructors. There is a possible ambiguity with -- postfix constructors: -- Assume _ * is a constructor. Then 'true *' can be parsed as either the -- intended _* applied to true, or as true applied to a variable *. If we -- check arities this problem won't appear. parsePattern :: Pattern -> ScopeM Pattern parsePattern = parsePatternOrSyn IsLHS parsePatternSyn :: Pattern -> ScopeM Pattern parsePatternSyn = parsePatternOrSyn IsPatSyn parsePatternOrSyn :: LHSOrPatSyn -> Pattern -> ScopeM Pattern parsePatternOrSyn lhsOrPatSyn p = billToParser $ do res <- parseLHS' lhsOrPatSyn Nothing p case res of Left p -> return p _ -> typeError $ NoParseForLHS lhsOrPatSyn p -- | Helper function for 'parseLHS' and 'parsePattern'. validConPattern :: [QName] -> Pattern -> Bool validConPattern cons p = case appView p of [_] -> True IdentP x : ps -> elem x cons && all (validConPattern cons) ps [QuoteP _, _] -> True _ -> False -- Andreas, 2012-06-04: I do not know why the following line was -- the catch-all case. It seems that the new catch-all works also -- and is more logical. -- ps -> all (validConPattern cons) ps -- | Helper function for 'parseLHS' and 'parsePattern'. appView :: Pattern -> [Pattern] appView p = case p of AppP p a -> appView p ++ [namedArg a] OpAppP _ op _ ps -> IdentP op : map namedArg ps ParenP _ p -> appView p RawAppP _ _ -> __IMPOSSIBLE__ HiddenP _ _ -> __IMPOSSIBLE__ InstanceP _ _ -> __IMPOSSIBLE__ _ -> [p] -- | Return all qualifiers occuring in a list of 'QName's. -- Each qualifier is returned as a list of names, e.g. -- for @Data.Nat._+_@ we return the list @[Data,Nat]@. qualifierModules :: [QName] -> [[Name]] qualifierModules qs = nub $ filter (not . null) $ map (init . qnameParts) qs -- | Parse a list of expressions into an application. parseApplication :: [Expr] -> ScopeM Expr parseApplication [e] = return e parseApplication es = billToParser $ do -- Build the parser let ms = qualifierModules [ q | Ident q <- es ] flat <- flattenScope ms <$> getScope p <- buildParsers (getRange es) flat UseBoundNames -- Parse case force $ parse (pTop p) es of [e] -> return e [] -> typeError $ NoParseForApplication es es' -> typeError $ AmbiguousParseForApplication es $ map fullParen es' parseModuleIdentifier :: Expr -> ScopeM QName parseModuleIdentifier (Ident m) = return m parseModuleIdentifier e = typeError $ NotAModuleExpr e parseRawModuleApplication :: [Expr] -> ScopeM (QName, [NamedArg Expr]) parseRawModuleApplication es = billToParser $ do let e : es_args = es m <- parseModuleIdentifier e -- Build the arguments parser let ms = qualifierModules [ q | Ident q <- es_args ] flat <- flattenScope ms <$> getScope p <- buildParsers (getRange es_args) flat UseBoundNames -- Parse case {-force $-} parse (pArgs p) es_args of -- TODO: not sure about forcing [as] -> return (m, as) [] -> typeError $ NoParseForApplication es ass -> do let f = fullParen . foldl (App noRange) (Ident m) typeError $ AmbiguousParseForApplication es $ map f ass -- | Parse an expression into a module application -- (an identifier plus a list of arguments). parseModuleApplication :: Expr -> ScopeM (QName, [NamedArg Expr]) parseModuleApplication (RawApp _ es) = parseRawModuleApplication es parseModuleApplication (App r e1 e2) = do -- TODO: do we need this case? (m, args) <- parseModuleApplication e1 return (m, args ++ [e2]) parseModuleApplication e = do m <- parseModuleIdentifier e return (m, []) --------------------------------------------------------------------------- -- * Inserting parenthesis --------------------------------------------------------------------------- fullParen :: IsExpr e => e -> e fullParen e = case exprView $ fullParen' e of ParenV e -> e e' -> unExprView e' fullParen' :: IsExpr e => e -> e fullParen' e = case exprView e of LocalV _ -> e WildV _ -> e OtherV _ -> e HiddenArgV _ -> e InstanceArgV _ -> e ParenV _ -> e AppV e1 (Common.Arg info e2) -> par $ unExprView $ AppV (fullParen' e1) (Common.Arg info e2') where e2' = case argInfoHiding info of Hidden -> e2 Instance -> e2 NotHidden -> fullParen' <$> e2 OpAppV x ns es -> par $ unExprView $ OpAppV x ns $ (map . fmap . fmap . fmap) fullParen' es LamV bs e -> par $ unExprView $ LamV bs (fullParen e) where par = unExprView . ParenV