{- HetCATS/Id.hs

$Id$

Authors: Klaus L�ttich

Christian Maeder

Year: 2002

This module supplies simple and mixfix identifiers.

A simple identifier is a lexical token given by a string and a start position.

The ordering of tokens ignores position information.

A place within mixfix identifiers is also a token.

Mixfix identifiers may also have a compound list.

This compound list follows the last non-place token!

-}

module Id (module Id, module ParsecPos) where

import Char

import ParsecPos

-- identifiers, fixed for all logics

type Pos = SourcePos

nullPos :: Pos

nullPos = newPos "" 0 0

headPos :: [Pos] -> Pos

headPos l = if null l then nullPos else head l

tailPos :: [Pos] -> [Pos]

tailPos l = if null l then [] else tail l

nullPosList :: [Pos]

nullPosList = nullPos:nullPosList

type Region = (Pos,Pos)

-- tokens as supplied by the scanner

data Token = Token { tokStr :: String

, tokPos :: Pos

} deriving (Show)

showTok :: Token -> ShowS

showTok = showString . tokStr

instance Eq Token where

Token s1 _ == Token s2 _ = s1 == s2

instance Ord Token where

Token s1 _ <= Token s2 _ = s1 <= s2

-- shortcut to get [Pos]

toPos :: Token -> [Token] -> Token -> [Pos]

toPos o l c = map tokPos (o:l++[c])

showSepList :: ShowS -> (a -> ShowS) -> [a] -> ShowS

showSepList _ _ [] = id

showSepList _ f [x] = f x

showSepList s f (x:r) = f x . s . showSepList s f r

-- special tokens

type Keyword = Token

type TokenOrPlace = Token

place :: String

place = "__"

isPlace :: TokenOrPlace -> Bool

isPlace (Token t _) = t == place

-- an identifier may be mixfix (though not for a sort) and compound

-- TokenOrPlace list must be non-empty!

data Id = Id [TokenOrPlace] [Id] [Pos]

-- pos of "[", commas, "]"

deriving (Show)

-- for pretty printing see PrettyPrint.hs

instance Eq Id where

Id tops1 ids1 _ == Id tops2 ids2 _ = tops1 == tops2 && ids1 == ids2

instance Ord Id where

Id tops1 ids1 _ <= Id tops2 ids2 _ =

if tops1 <= tops2 then

if tops2 <= tops1 then ids1 <= ids2 else True

else False

noShow :: Bool -> ShowS -> ShowS

noShow b s = if b then id else s

showIds :: [Id] -> ShowS

showIds is = noShow (null is) $ showString "["

. showSepList (showString ",") showId is

. showString "]"

showId :: Id -> ShowS

showId (Id ts is _) =

let (toks, places) = splitMixToken ts

showToks = showSepList id showTok

in showToks toks . showIds is . showToks places

splitMixToken :: [Token] -> ([Token],[Token])

splitMixToken l = let (pls, toks) = span isPlace (reverse l) in

(reverse toks, reverse pls)

-- compute a meaningful single position for diagnostics

posOfId :: Id -> Pos

posOfId (Id [] _ _) = error "Id.posOfId"

posOfId (Id ts _ _) = let l = dropWhile isPlace ts

in if null l then -- for invisible "__ __" (only places)

let h = head ts

in incSourceColumn (tokPos h)

$ length (tokStr h)

else tokPos $ head l

-- Simple Ids

type SIMPLE_ID = Token

mkSimpleId :: String -> Token

mkSimpleId s = Token s nullPos

simpleIdToId :: SIMPLE_ID -> Id

simpleIdToId sid = Id [sid] [] []

---- some useful predicates for Ids -------------------------------------

isOrdAppl :: Id -> Bool

isOrdAppl = not . isMixfix

isMixfix :: Id -> Bool

isMixfix (Id tops _ _) = any isPlace tops

isPrefix :: Id -> Bool

isPrefix (Id tops _ _) = (not . isPlace . head) tops

&& (isPlace . last) tops

isPostfix :: Id -> Bool

isPostfix (Id tops _ _) = (isPlace . head) tops

&& (not . isPlace . last) tops

isInfix2 :: Id -> Bool

isInfix2 (Id tops _ _)

| length tops == 3 = (isPlace . head) tops

&& (isPlace . last) tops

&& (not . isPlace . head . tail) tops

| otherwise = False

isInfix :: Id -> Bool

isInfix (Id tops _ _) = (isPlace . head) tops

&& (isPlace . last) tops

isSurround :: Id -> Bool

isSurround i@(Id tops _ _) = (not . isPlace . head) tops

&& (not . isPlace . last) tops

&& (isMixfix i)

isCompound :: Id -> Bool

isCompound (Id _ cs _) = not $ null cs

---- helper class -------------------------------------------------------

{- This class is derivable with DrIFT in HetCATS/utils !

It's main purpose is to have an function that "works" on every

constructor with a Pos or [Pos] field. During parsing, mixfix

analysis and ATermConversion this function might be very useful.

-}

class PosItem a where

up_pos :: (Pos -> Pos) -> a -> a

up_pos_l :: ([Pos] -> [Pos]) -> a -> a

get_pos :: a -> Maybe Pos

get_pos_l :: a -> Maybe [Pos]

up_pos_err :: String -> a

up_pos_err fn =

error ("function \"" ++ fn ++ "\" is not implemented")

up_pos _ = id

up_pos_l _ = id

get_pos _ = Nothing

get_pos_l _ = Nothing

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

-- Two fine instances, DrIFTed but handcopied and extended

instance PosItem Token where

up_pos fn1 (Token aa ab) = (Token aa (fn1 ab))

get_pos (Token _ ab) = Just ab

instance PosItem Id where

up_pos_l fn1 (Id aa ab ac) = (Id aa ab (fn1 ac))

get_pos_l (Id _ _ ac) = Just ac

get_pos = Just . posOfId