{- |

Module : $Header$

Description : Parser for basic specs

Copyright : (c) Dominik Dietrich, DFKI Bremen 2010

License : similar to LGPL, see HetCATS/LICENSE.txt or LIZENZ.txt

Maintainer : dominik.dietrich@dfki.de

Stability : experimental

Portability : portable

Parser for abstract syntax for reduce computer algebra system

-}

module Reduce.Parse_AS_Basic

where

import qualified Common.AnnoState as AnnoState

import Common.Id as Id

import Common.Keywords as Keywords

import Common.Lexer as Lexer

import Control.Monad

import Reduce.AS_BASIC_Reduce

import Reduce.Keywords

import Text.ParserCombinators.Parsec

-- the basic lexer, test using e.g. runParser identifier 0 "" "asda2_3"

-----------------------------------------------------------------------------

--------------------------- Parser for Expressions --------------------------

-----------------------------------------------------------------------------

-- | parsing of identifiers. an identifier is a letter followed by letters/numbers/_, but not a keyword

identifier :: CharParser st Id.Token

identifier = Lexer.pToken $ Lexer.reserved allKeywords Lexer.scanAnyWords

-- | parser for numbers (both integers and floats) without signs

number :: CharParser st Id.Token

number = Lexer.pToken Lexer.scanFloat

expression :: CharParser st EXPRESSION

expression = do

exp1 <- factor

exps <- many $ liftM2 (,) (Lexer.keySign (string "+" <|> string "-")) factor

if null exps then return exp1

else return $ foldr (\ a b -> (Op (fst a) [b,(snd a)] nullRange)) exp1 exps

<|>

listexp

-- | parse a product of basic expressions

factor :: CharParser st EXPRESSION

factor = do

exp1 <- expexp

exps <- many $ liftM2 (,) (Lexer.keySign (string "*" <|> string "/")) factor

if null exps then return exp1

else return $ foldr (\ a b -> (Op (fst a) [b,(snd a)] nullRange)) exp1 exps

-- | parse a sequence of exponentiations

expexp :: CharParser st EXPRESSION

expexp = do

exp1 <- expatom

exps <- many $ liftM2 (,) (Lexer.keySign (string "**" <|> string "^")) expexp

if null exps then return exp1

else return $ foldr (\ a b -> (Op (fst a) [b,(snd a)] nullRange)) exp1 exps

-- | parse a basic expression

expatom :: CharParser st EXPRESSION

expatom = do

nr <- number

if (isFloating nr) then return (Double (read (tokStr nr)) (tokPos nr))

else return (Int (read (tokStr nr)) (tokPos nr))

<|>

do

ident <- identifier

return (Var ident)

<|>

do

oParenT

expr <- expression

cParenT

return expr

-- | parses a list expression

listexp :: CharParser st EXPRESSION

listexp = do

(Lexer.keySign (string "{"))

elems <- Lexer.separatedBy expression (Lexer.keySign (string ","))

(Lexer.keySign (string "}"))

return (List (fst elems) nullRange)

-----------------------------------------------------------------------------

---------------------------- parser for formulas ----------------------------

-----------------------------------------------------------------------------

-- | parser for atoms

truefalseFormula :: CharParser st EXPRESSION

truefalseFormula =

do

(lexemeParser (Lexer.keySign (string "true")))

return (Op "True" [] nullRange)

<|>

do

(lexemeParser (Lexer.keySign (string "false")))

return (Op "False" [] nullRange)

-- | parser for predicates

predFormula :: CharParser st EXPRESSION

predFormula =

do

exp1 <- expression

op <- (Lexer.keySign (try (string "<=") <|> try (string ">=") <|> try (string "=") <|> try (string "<") <|> try (string ">")))

exp2 <- expression

return (Op op [exp1,exp2] nullRange)

atomicFormula :: CharParser st EXPRESSION

atomicFormula = truefalseFormula <|> predFormula <|> parenFormula

-- | parser for formulas

aFormula :: CharParser st EXPRESSION

aFormula = (try negFormula) <|> impOrFormula

-- | parser for symbols followed by whitechars

lexemeParser :: CharParser st a -> CharParser st a

lexemeParser p1 = do

res <- p1

skip

return res

negFormula :: CharParser st EXPRESSION

negFormula = do

(lexemeParser (Lexer.keySign (string "not")))

f <- atomicFormula

return (Op "Not" [f] nullRange)

-- | parses a formula within brackets

parenFormula :: CharParser st EXPRESSION

parenFormula = do

oParenT

f <- aFormula

cParenT

return f

-- | parser for implications and ors (same precedence)

impOrFormula :: CharParser st EXPRESSION

impOrFormula = do

f1 <- andFormula

opfs <- many $ liftM2 (,) (lexemeParser (Lexer.keySign (string "or" <|> string "impl"))) impOrFormula

if null opfs then return f1

else return $ foldr (\ (a1,a2) b -> case a1 of

"or" -> Op "Or" [b,a2] nullRange

"impl" -> Op "Impl" [b,a2] nullRange

_ -> error "impl or or expected"

) f1 opfs

-- | a parser for and sequence of and formulas

andFormula :: CharParser st EXPRESSION

andFormula = do

f1 <- atomicFormula

opfs <- many $ liftM2 (,) (lexemeParser (Lexer.keySign (string "and"))) atomicFormula

if null opfs then return f1

else return $ foldr (\ a b -> (Op "And" [b,(snd a)] nullRange)) f1 opfs

-----------------------------------------------------------------------------

---------------------------- Parser for Commands ----------------------------

-----------------------------------------------------------------------------

formulaorexpression :: CharParser st EXPRESSION

formulaorexpression = ((try aFormula) <|> expression)

-- | parser for commands

command :: CharParser st CMD

command = do

cmd <- (lexemeParser (Lexer.keySign (try (string "solve")) <|> string "simplify" <|> string "remainder" <|> string "gcd" <|> string "int" <|> string "qelim"))

oParenT

arg1 <- formulaorexpression

args <- many $ liftM2 (,) (lexemeParser (Lexer.keySign (string ","))) formulaorexpression

cParenT

return (Cmd cmd (arg1 : (map snd args)))

-----------------------------------------------------------------------------

--------------------------- parser spec entries. ----------------------------

-----------------------------------------------------------------------------

-- | parser for operator declarations: example: operator a,b,c

opItem :: CharParser st OP_ITEM

opItem = do

Lexer.keySign (lexemeParser (string "operator"))

var1 <- identifier

vars <- many $ liftM2 (,) (lexemeParser (Lexer.keySign (string ","))) identifier

return (Op_item (var1:(map snd vars)) nullRange)

-- | Toplevel parser for basic specs

basicSpec :: AnnoState.AParser st BASIC_SPEC

basicSpec =

fmap Basic_spec (AnnoState.annosParser parseBasicItems)

<|> (Lexer.oBraceT >> Lexer.cBraceT >> return (Basic_spec []))

-- | Parser for basic items

parseBasicItems :: AnnoState.AParser st BASIC_ITEMS

parseBasicItems = parseOpDecl <|> parseAxItems

-- | parser for predicate declarations

parseOpDecl :: AnnoState.AParser st BASIC_ITEMS

parseOpDecl = fmap Op_decl opItem

-- | parser for Axiom_item

parseAxItems :: AnnoState.AParser st BASIC_ITEMS

parseAxItems = do

AnnoState.dotT

cmd <- (AnnoState.allAnnoParser command)

return $ Axiom_item cmd

-----------------------------------------------------------------------------

------------------------ parser for symbol maps etc. ------------------------

-----------------------------------------------------------------------------

-- | parsing a prop symbol

symb :: GenParser Char st SYMB

symb = fmap Symb_id identifier

-- | parsing one symbol or a mapping of one to a second symbol

symbMap :: GenParser Char st SYMB_OR_MAP

symbMap = do

s <- symb

do f <- pToken $ toKey mapsTo

t <- symb

return (Symb_map s t $ tokPos f)

<|> return (Symb s)

-- | Parse a list of comma separated symbols.

symbItems :: GenParser Char st SYMB_ITEMS

symbItems = do

(is, ps) <- symbs

return (Symb_items is $ catRange ps)

-- | parse a comma separated list of symbols

symbs :: GenParser Char st ([SYMB], [Token])

symbs = do

s <- symb

do c <- commaT `followedWith` symb

(is, ps) <- symbs

return (s:is, c:ps)

<|> return ([s], [])

-- | parse a list of symbol mappings

symbMapItems :: GenParser Char st SYMB_MAP_ITEMS

symbMapItems = do

(is, ps) <- symbMaps

return (Symb_map_items is $ catRange ps)

-- | parse a comma separated list of symbol mappings

symbMaps :: GenParser Char st ([SYMB_OR_MAP], [Token])

symbMaps = do

s <- symbMap

do c <- commaT `followedWith` symb

(is, ps) <- symbMaps

return (s:is, c:ps)

<|> return ([s], [])