{- |

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 Common.Parsec

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, or _, but not a keyword -}

identifier :: CharParser st Id.Token

identifier = Lexer.pToken $ 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 $ pair (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 $ pair (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 $ pair (Lexer.keySign $ tryString "**" <|> 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.keyWord (tryString "true"))

return (Op "True" [] nullRange)

<|>

do

lexemeParser (Lexer.keyWord (tryString "false"))

return (Op "False" [] nullRange)

-- | parser for predicates

predFormula :: CharParser st EXPRESSION

predFormula =

do

exp1 <- expression

op <- Lexer.keySign $ tryString "<=" <|> tryString ">="

<|> single (oneOf "=<>")

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 = (<< skip)

negFormula :: CharParser st EXPRESSION

negFormula = do

lexemeParser (Lexer.keyWord (tryString "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 $ pair (lexemeParser $ Lexer.keyWord

$ tryString "or" <|> tryString "impl") impOrFormula

if null opfs then return f1

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

"or" -> "Or"

"impl" -> "Impl"

_ -> error "impl or or expected")

[b,a2] nullRange

) f1 opfs

-- | a parser for and sequence of and formulas

andFormula :: CharParser st EXPRESSION

andFormula = do

f1 <- atomicFormula

opfs <- many $ pair (lexemeParser $ keyWord $ tryString "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.keyWord $ choice $ map tryString

["solve", "simplify", "remainder", "gcd", "int", "qelim"]

oParenT

arg1 <- formulaorexpression

args <- many $ pair (lexemeParser $ 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 (tryString "operator"))

var1 <- identifier

vars <- many $ pair (lexemeParser $ 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], [])