{- |

Module : $Header$

Copyright : (c) Christian Maeder and Uni Bremen 2002-2004

Licence : similar to LGPL, see HetCATS/LICENCE.txt or LIZENZ.txt

Maintainer : maeder@tzi.de

Stability : provisional

Portability : portable

parser for HasCASL kinds, types, terms, patterns and equations

-}

module HasCASL.ParseTerm where

import Common.AnnoState

import Common.Id

import Common.Keywords

import Common.Lexer

import Common.Token

import HasCASL.HToken

import HasCASL.As

import Text.ParserCombinators.Parsec

import Data.List

import Data.Maybe

-- * key sign tokens

-- | keywords for the variance of kinds

plusT, minusT :: AParser st Token

plusT = asKey plusS

minusT = asKey minusS

-- | a colon not followed by a question mark

colT :: AParser st Token

colT = asKey colonS

-- | a colon immediately followed by a question mark

qColonT :: AParser st Token

qColonT = asKey (colonS++quMark)

-- * parser for bracketed lists

-- | a generic bracket parser

bracketParser :: AParser st a -> AParser st Token -> AParser st Token

-> AParser st Token -> ([a] -> [Pos] -> b) -> AParser st b

bracketParser parser op cl sep k =

do o <- op

(ts, ps) <- option ([], []) (parser `separatedBy` sep)

c <- cl

return (k ts (toPos o ps c))

-- | parser for square brackets

mkBrackets :: AParser st a -> ([a] -> [Pos] -> b) -> AParser st b

mkBrackets p c = bracketParser p oBracketT cBracketT anComma c

-- | parser for braces

mkBraces :: AParser st a -> ([a] -> [Pos] -> b) -> AParser st b

mkBraces p c = bracketParser p oBraceT cBraceT anComma c

-- * kinds

-- | parse a simple class name or the type universe as kind

parseClassId :: AParser st Kind

parseClassId = fmap (\c -> if showId c "" == "Type"

then Intersection [] [posOfId c]

else ClassKind c MissingKind) classId

-- | do 'parseClassId' or a downset or an intersection kind

parseSimpleKind :: AParser st Kind

parseSimpleKind = parseClassId

<|>

do o <- oParenT

(cs, ps) <- kind `separatedBy` anComma

c <- cParenT

return (if isSingle cs then head cs else

Intersection cs (toPos o ps c))

<|>

do o <- oBraceT

i <- pToken scanHCWords

d <- dotT

j <- asKey (tokStr i)

l <- lessT

t <- parseType

p <- cBraceT

return (Downset (Just i) t MissingKind

(map tokPos [o,d,j,l,p]))

-- | do 'parseSimpleKind' and check for an optional 'Variance'

parseExtKind :: AParser st Kind

parseExtKind = do k <- parseSimpleKind

do s <- plusT

return (ExtKind k CoVar [tokPos s])

<|>

do m <- minusT

return (ExtKind k ContraVar [tokPos m])

<|> return k

-- | parse a (right associative) function kind for a given argument kind

arrowKind :: Kind -> AParser st Kind

arrowKind k1 =

do a <- asKey funS

k2 <- kind

return (FunKind k1 k2 $ [tokPos a])

-- | parse a function kind but reject an extended kind

kind :: AParser st Kind

kind =

do k1 <- parseExtKind

arrowKind k1 <|> case k1 of

ExtKind _ _ _ -> unexpected "variance of kind"

_ -> return k1

-- | parse a function kind but accept an extended kind

extKind :: AParser st Kind

extKind =

do k1 <- parseExtKind

arrowKind k1 <|> return k1

-- * type variables

-- a (simple) type variable with a 'Variance'

extVar :: AParser st Id -> AParser st (Id, Maybe Variance, Pos)

extVar vp =

do t <- vp

do a <- plusT

return (t, Just CoVar, tokPos a)

<|>

do a <- minusT

return (t, Just ContraVar, tokPos a)

<|> return (t, Nothing, nullPos)

-- several 'extTypeVar' with a 'Kind'

typeVars :: AParser st [TypeArg]

typeVars = do (ts, ps) <- extVar typeVar `separatedBy` anComma

typeKind ts ps

allIsInVar :: [(TypeId, Maybe Variance, Pos)] -> Bool

allIsInVar = all ( \ (_, v, _) -> isNothing v)

-- 'parseType' a 'Downset' starting with 'lessT'

typeKind :: [(TypeId, Maybe Variance, Pos)] -> [Token] -> AParser st [TypeArg]

typeKind vs ps =

do c <- colT

if allIsInVar vs then

do k <- extKind

return (makeTypeArgs vs ps [tokPos c] k)

else do k <- kind

return (makeTypeArgs vs ps [tokPos c] k)

<|>

do l <- lessT

t <- parseType

return (makeTypeArgs vs ps [tokPos l]

(Downset Nothing t MissingKind []))

<|> return (makeTypeArgs vs ps [] star)

-- | add the 'Kind' to all 'extTypeVar' and yield a 'TypeArg'

makeTypeArgs :: [(TypeId, Maybe Variance, Pos)] -> [Token]

-> [Pos] -> Kind -> [TypeArg]

makeTypeArgs ts ps qs k =

zipWith (mergeVariance Comma k) (init ts)

(map ((:[]). tokPos) ps)

++ [mergeVariance Other k (last ts) qs]

where mergeVariance c e (t, Nothing, _) q =

TypeArg t e c q

mergeVariance c e (t, Just v, p) q =

TypeArg t (ExtKind e v [p]) c q

-- | a single 'TypeArg' (parsed by 'typeVars')

singleTypeArg :: AParser st TypeArg

singleTypeArg = do as <- typeVars

case as of

[a] -> return a

_ -> unexpected "list of type arguments"

-- | a 'singleTypArg' put in parentheses

parenTypeArg :: AParser st (TypeArg, [Token])

parenTypeArg =

do o <- oParenT

a <- singleTypeArg

p <- cParenT

return (a, [o, p])

-- | a 'singleTypeArg' possibly put in parentheses

typeArg :: AParser st (TypeArg, [Token])

typeArg =

do a <- singleTypeArg

return (a, [])

<|> parenTypeArg

-- | several 'typeArg's

typeArgs :: AParser st ([TypeArg], [Token])

typeArgs =

do l <- many1 typeArg

return (map fst l, concatMap snd l)

-- | a 'singleTypeArg' put in parentheses as 'TypePattern'

typePatternArg :: AParser st TypePattern

typePatternArg =

do (a, ps) <- parenTypeArg

return $ TypePatternArg a $ map tokPos ps

-- * parse special identifier tokens

type TokenMode = [String]

-- | parse a 'Token' of an 'Id' (to be declared)

-- but exclude the signs in 'TokenMode'

aToken :: TokenMode -> AParser st Token

aToken b = pToken (scanQuotedChar <|> scanDigit <|> scanHCWords <|> placeS <|>

reserved b scanHCSigns)

-- | just 'aToken' only excluding basic HasCASL keywords

idToken :: AParser st Token

idToken = aToken [] <|> pToken scanDotWords

-- * type patterns

-- 'TypePatternToken's within 'BracketTypePattern's

-- may recusively be 'idToken's.

-- Parenthesis are only legal for a 'typePatternArg'.

primTypePatternOrId :: AParser st TypePattern

primTypePatternOrId = fmap TypePatternToken idToken

<|> mkBraces typePatternOrId (BracketTypePattern Braces)

<|> mkBrackets typePatternOrId (BracketTypePattern Squares)

<|> typePatternArg

-- several 'primTypePatternOrId's possibly yielding a 'MixfixTypePattern'

typePatternOrId :: AParser st TypePattern

typePatternOrId = do ts <- many1 primTypePatternOrId

return( if isSingle ts then head ts

else MixfixTypePattern ts)

-- | those (top-level) 'Token's (less than 'idToken')

-- that may appear in 'TypePattern's as 'TypePatternToken'.

typePatternToken :: AParser st TypePattern

typePatternToken = fmap TypePatternToken (pToken (scanHCWords <|> placeS <|>

reserved [assignS, lessS, equalS] scanHCSigns))

-- | a 'typePatternToken' or something in braces (a 'typePattern'),

-- in square brackets (a 'typePatternOrId' covering compound lists)

-- or parenthesis ('typePatternArg')

primTypePattern :: AParser st TypePattern

primTypePattern = typePatternToken

<|> mkBrackets typePatternOrId (BracketTypePattern Squares)

<|> mkBraces typePattern (BracketTypePattern Braces)

<|> typePatternArg

-- several 'primTypePatter's possibly yielding a 'MixfixTypePattern'

typePattern :: AParser st TypePattern

typePattern = do ts <- many1 primTypePattern

let t = if isSingle ts then head ts

else MixfixTypePattern ts

in return t

-- * types

-- a parsed type may also be interpreted as a kind (by the mixfix analysis)

-- | type tokens with some symbols removed

typeToken :: AParser st Type

typeToken = fmap TypeToken (pToken (scanHCWords <|> placeS <|>

reserved (assignS : lessS : equalS : barS :

hascasl_type_ops)

scanHCSigns))

-- | 'TypeToken's within 'BracketType's may recusively be

-- 'idToken's. Parenthesis may group a mixfix type

-- or may be interpreted as 'Intersection' later in a GEN-VAR-DECL.

primTypeOrId :: AParser st Type

primTypeOrId = fmap TypeToken idToken

<|> mkBrackets typeOrId (BracketType Squares)

<|> mkBraces typeOrId (BracketType Braces)

<|> bracketParser typeOrId oParenT cParenT anComma

(BracketType Parens)

-- | several 'primTypeOrId's possibly yielding a 'MixfixType'

-- and possibly followed by a 'kindAnno'.

typeOrId :: AParser st Type

typeOrId = do ts <- many1 primTypeOrId

let t = if isSingle ts then head ts

else MixfixType ts

in

kindAnno t

<|>

return(t)

-- | a 'Kind' annotation starting with 'colT'.

kindAnno :: Type -> AParser st Type

kindAnno t = do c <- colT

k <- kind

return (KindedType t k [tokPos c])

-- | a typeToken' or a 'BracketType'. Square brackets may contain 'typeOrId'.

primType :: AParser st Type

primType = typeToken

<|> mkBrackets typeOrId (BracketType Squares)

<|> mkBraces parseType (BracketType Braces)

<|> bracketParser parseType oParenT cParenT anComma

(BracketType Parens)

-- | a 'primType' possibly preceded by 'quMarkT'

lazyType :: AParser st Type

lazyType = do q <- quMarkT

t <- primType

return (LazyType t [tokPos q])

<|> primType

-- | several 'lazyType's (as 'MixfixType') possibly followed by 'kindAnno'

mixType :: AParser st Type

mixType = do ts <- many1 lazyType

let t = if isSingle ts then head ts else MixfixType ts

in kindAnno t

<|> return t

-- | 'mixType' possibly interspersed with 'crossT'

prodType :: AParser st Type

prodType = do (ts, ps) <- mixType `separatedBy` crossT

return $ mkProductType ts (map tokPos ps)

-- | a (right associativ) function type

parseType :: AParser st Type

parseType =

do t1 <- prodType

do a <- arrowT <?> funS

t2 <- parseType

return $ FunType t1 (fst a) t2 [snd a]

<|> return t1

-- | parse one of the four possible 'Arrow's

arrowT :: AParser st (Arrow, Pos)

arrowT = do a <- asKey funS

return (FunArr, tokPos a)

<|>

do a <- asKey pFun

return (PFunArr, tokPos a)

<|>

do a <- asKey contFun

return (ContFunArr, tokPos a)

<|>

do a <- asKey pContFun

return (PContFunArr, tokPos a)

-- | parse a 'TypeScheme' using 'forallT', 'typeVars', 'dotT' and 'parseType'

typeScheme :: AParser st TypeScheme

typeScheme = do f <- forallT

(ts, cs) <- typeVars `separatedBy` anSemi

d <- dotT

t <- typeScheme

return $ case t of

TypeScheme ots q ps ->

TypeScheme (concat ts ++ ots) q

(toPos f cs d ++ ps)

<|> fmap simpleTypeScheme parseType

data TypeOrTypeScheme = PartialType Type | TotalTypeScheme TypeScheme

-- a 'TypeOrTypescheme' for a possibly partial constant (given by 'qColonT')

typeOrTypeScheme :: AParser st (Token, TypeOrTypeScheme)

typeOrTypeScheme = do q <- qColonT

t <- parseType

return (q, PartialType t)

<|>

do q <- colT

s <- typeScheme

return (q, TotalTypeScheme s)

toPartialTypeScheme :: [Pos] -> TypeOrTypeScheme -> TypeScheme

toPartialTypeScheme qs ts = case ts of

PartialType t -> simpleTypeScheme $ liftType t qs

TotalTypeScheme s -> s

partialTypeScheme :: AParser st (Token, TypeScheme)

partialTypeScheme = do (c, ts) <- typeOrTypeScheme

return (c, toPartialTypeScheme [tokPos c] ts)

-- * varDecls and genVarDecls

-- | comma separated 'var' with 'varDeclType'

varDecls :: AParser st [VarDecl]

varDecls = do (vs, ps) <- var `separatedBy` anComma

varDeclType vs ps

-- | a type ('parseType') following a 'colT'

varDeclType :: [Var] -> [Token] -> AParser st [VarDecl]

varDeclType vs ps = do c <- colT

t <- parseType

return (makeVarDecls vs ps t (tokPos c))

-- | attach the 'Type' to every 'Var'

makeVarDecls :: [Var] -> [Token] -> Type -> Pos -> [VarDecl]

makeVarDecls vs ps t q = zipWith (\ v p -> VarDecl v t Comma [tokPos p])

(init vs) ps ++ [VarDecl (last vs) t Other [q]]

-- | either like 'varDecls' or type variables with a 'typeDownset'.

-- A 'GenVarDecl' may later become a 'GenTypeVarDecl'.

genVarDecls:: AParser st [GenVarDecl]

genVarDecls = do (vs, ps) <- extVar var `separatedBy` anComma

if allIsInVar vs then

fmap (map GenVarDecl)

(varDeclType

(map ( \ (i, _, _) -> i) vs) ps)

<|> fmap (map GenTypeVarDecl)

(typeKind vs ps)

else fmap (map GenTypeVarDecl)

(typeKind vs ps)

-- * patterns

{- | different legal 'PatternToken's possibly excluding 'funS' or

'equalS' for case or let patterns resp. -}

tokenPattern :: TokenMode -> AParser st Pattern

tokenPattern b = fmap TermToken (aToken b <|> pToken (string "_"))

-- a single underscore serves as wildcard pattern

-- | 'tokenPattern' or 'BracketPattern'

primPattern :: TokenMode -> AParser st Pattern

primPattern b = tokenPattern b

<|> mkBrackets pattern (BracketTerm Squares)

<|> mkBraces pattern (BracketTerm Braces)

<|> bracketParser pattern oParenT cParenT anComma

(BracketTerm Parens)

-- | several 'typedPattern'

mixPattern :: TokenMode -> AParser st Pattern

mixPattern b =

do l <- many1 $ asPattern b

return $ if isSingle l then head l else MixfixTerm l

-- | a possibly typed ('parseType') pattern

typedPattern :: TokenMode -> AParser st Pattern

typedPattern b =

do t <- primPattern b

do c <- colT

ty <- parseType

return (MixfixTerm [t, MixTypeTerm OfType ty [tokPos c]])

<|> return t

-- | top-level pattern (possibly 'AsPattern')

asPattern :: TokenMode -> AParser st Pattern

asPattern b =

do v <- typedPattern b

case v of

TermToken tt -> if isPlace tt then return v else do

c <- asKey asP

t <- typedPattern b

return (AsPattern

(VarDecl (mkId [tt]) (MixfixType []) Other [tokPos c])

t [tokPos c])

<|> return v

_ -> return v

-- | an unrestricted 'asPattern'

pattern :: AParser st Pattern

pattern = mixPattern []

-- | a 'Total' or 'Partial' lambda dot

lamDot :: AParser st (Partiality, Token)

lamDot = do d <- asKey (dotS++exMark) <|> asKey (cDot++exMark)

return (Total,d)

<|>

do d <- dotT

return (Partial,d)

-- | patterns between 'lamS' and 'lamDot'

lamPattern :: AParser st [Pattern]

lamPattern =

do lookAhead lamDot

return []

<|> do p <- pattern

ps <- lamPattern

return (p : ps)

-- * terms

-- | an 'uninstOpId' possibly followed by types ('parseType') in brackets

-- and further places ('placeT')

instOpId :: AParser st InstOpId

instOpId = do i <- uninstOpId

(ts, qs) <- option ([], [])

(mkBrackets parseType (,))

return (InstOpId i ts qs)

{- | 'Token's that may occur in 'Term's including literals

'scanFloat', 'scanString' but excluding 'ifS', 'whenS' and 'elseS'

to allow a quantifier after 'whenS'. In case terms also 'barS' will

excluded on the top-levek. -}

tToken :: TokenMode -> AParser st Token

tToken b = pToken(scanFloat <|> scanString

<|> scanQuotedChar <|> scanDotWords

<|> reserved [ifS, whenS, elseS] scanHCWords

<|> reserved b scanHCSigns

<|> placeS <?> "id/literal" )

-- | 'tToken' as 'Term' plus 'exEqual' and 'equalS'

termToken :: TokenMode -> AParser st Term

termToken b = fmap TermToken (asKey exEqual <|> asKey equalS <|> tToken b)

-- | 'termToken' plus 'BracketTerm's

primTerm :: TokenMode -> AParser st Term

primTerm b = termToken b

<|> mkBraces termInParens (BracketTerm Braces)

<|> mkBrackets termInParens (BracketTerm Squares)

<|> bracketParser termInParens oParenT cParenT anComma

(BracketTerm Parens)

-- | how the keyword 'inS' should be treated

data InMode = NoIn -- ^ next 'inS' belongs to 'letS'

| WithIn -- ^ 'inS' is the element test

-- | all 'Term's that start with a unique keyword

baseTerm :: (InMode, TokenMode) -> AParser st Term

baseTerm b = ifTerm b

<|> whenTerm b

<|> forallTerm b

<|> exTerm b

<|> lambdaTerm b

<|> caseTerm b

<|> letTerm b

-- | 'whenS' possibly followed by an 'elseS'

whenTerm :: (InMode, TokenMode) -> AParser st Term

whenTerm b =

do i <- asKey whenS

c <- mixTerm b

do t <- asKey elseS

e <- mixTerm b

return (MixfixTerm [TermToken i, c, TermToken t, e])

<|> return (MixfixTerm [TermToken i, c])

-- | 'ifS' possibly followed by 'thenS' and 'elseS'

-- yielding a 'MixfixTerm'

ifTerm :: (InMode, TokenMode) -> AParser st Term

ifTerm b =

do i <- asKey ifS

c <- mixTerm b

do t <- asKey thenS

e <- mixTerm b

do s <- asKey elseS

f <- mixTerm b

return (MixfixTerm [TermToken i, c, TermToken t, e,

TermToken s, f])

<|> return (MixfixTerm [TermToken i, c, TermToken t, e])

<|> return (MixfixTerm [TermToken i, c])

-- | unrestricted terms including qualified names

termInParens :: AParser st Term

termInParens = term <|> varTerm <|> qualOpName <|> qualPredName

-- | a qualified 'var'

varTerm :: AParser st Term

varTerm =

do v <- asKey varS

i <- var

c <- colT

t <- parseType

return $ QualVar $ VarDecl i t Other $ toPos v [] c

-- | 'opS' or 'functS'

opBrand :: AParser st (Token, OpBrand)

opBrand = bind (,) (asKey opS) (return Op)

<|> bind (,) (asKey functS) (return Fun)

-- | a qualified operation (with 'opBrand')

qualOpName :: AParser st Term

qualOpName =

do (v, b) <- opBrand

i <- instOpId

(c, t) <- partialTypeScheme

return $ QualOp b i t $ toPos v [] c

-- | a qualified predicate

qualPredName :: AParser st Term

qualPredName =

do v <- asKey predS

i <- instOpId

c <- colT

t <- typeScheme

return $ QualOp Pred i (predTypeScheme t) $ toPos v [] c

-- | a qualifier expecting a further 'Type'.

-- 'inS' is rejected for 'NoIn'

typeQual :: InMode -> AParser st (TypeQual, Token)

typeQual m =

do q <- colT

return (OfType, q)

<|>

do q <- asT

return (AsType, q)

<|>

case m of

NoIn -> pzero

WithIn ->

do q <- asKey inS

return (InType, q)

-- | a possibly type qualified ('typeQual') 'primTerm' or a 'baseTerm'

typedTerm :: (InMode, TokenMode) -> AParser st Term

typedTerm (i, b) =

do t <- primTerm b

do (q, p) <- typeQual i

ty <- parseType

return (MixfixTerm [t, MixTypeTerm q ty [tokPos p]])

<|> return t

<|> baseTerm (i, b)

-- | several 'typedTerm's yielding a 'MixfixTerm'

mixTerm :: (InMode, TokenMode) -> AParser st Term

mixTerm b =

do ts <- many1 $ typedTerm b

return $ if isSingle ts then head ts else MixfixTerm ts

-- | keywords that start a new item

hasCaslStartKeywords :: [String]

hasCaslStartKeywords =

dotS:cDot: (hascasl_reserved_words \\ [existsS, letS, caseS])

-- | a 'mixTerm' followed by 'whereS' and equations separated by 'optSemi'

whereTerm :: (InMode, TokenMode) -> AParser st Term

whereTerm b =

do t <- mixTerm b

do p <- asKey whereS

(es, ps, _ans) <- itemAux hasCaslStartKeywords $

patternTermPair ([equalS]) b equalS

-- ignore collected annotations

return (LetTerm Where es t (map tokPos (p:ps)))

<|> return t

-- | a 'whereTerm' called with ('WithIn', [])

term :: AParser st Term

term = whereTerm (WithIn, [])

-- | a 'Universal' 'QuantifiedTerm'

forallTerm :: (InMode, TokenMode) -> AParser st Term

forallTerm b =

do f <- forallT

(vs, ps) <- genVarDecls `separatedBy` anSemi

addAnnos

d <- dotT

t <- mixTerm b

return $ QuantifiedTerm Universal (concat vs) t $ toPos f ps d

-- | 'Unique' or 'Existential'

exQuant :: AParser st (Token, Quantifier)

exQuant =

bind (,) (asKey (existsS++exMark)) (return Unique)

<|> bind (,) (asKey existsS) (return Existential)

-- | a (possibly unique) existential 'QuantifiedTerm'

exTerm :: (InMode, TokenMode) -> AParser st Term

exTerm b =

do (p, q) <- exQuant <?> existsS

(vs, ps) <- varDecls `separatedBy` anSemi

d <- dotT

f <- mixTerm b

return $ QuantifiedTerm q (map GenVarDecl (concat vs)) f $ toPos p ps d

-- | a 'LambdaTerm'

lambdaTerm :: (InMode, TokenMode) -> AParser st Term

lambdaTerm b =

do l <- asKey lamS

pl <- lamPattern

(k, d) <- lamDot

t <- mixTerm b

return (LambdaTerm pl k t (toPos l [] d))

-- | a 'CaseTerm' with 'funS' excluded in 'patternTermPair'

caseTerm :: (InMode, TokenMode) -> AParser st Term

caseTerm (i, _) =

do c <- asKey caseS

t <- term

o <- asKey ofS

(ts, ps) <- patternTermPair [funS] (i, [barS]) funS

`separatedBy` barT

return (CaseTerm t ts (map tokPos (c:o:ps)))

-- | a 'LetTerm' with 'equalS' excluded in 'patternTermPair'

-- (called with 'NoIn')

letTerm :: (InMode, TokenMode) -> AParser st Term

letTerm b =

do l <- asKey letS

(es, ps) <- patternTermPair [equalS] (NoIn, []) equalS

`separatedBy` anSemi

i <- asKey inS

t <- mixTerm b

return (LetTerm Let es t (toPos l ps i))

-- | a customizable pattern equation

patternTermPair :: TokenMode -> (InMode, TokenMode) -> String

-> AParser st ProgEq

patternTermPair b1 b2 sep =

do p <- mixPattern b1

s <- asKey sep

t <- mixTerm b2

return (ProgEq p t (tokPos s))