{-# OPTIONS -fallow-undecidable-instances #-}

{- |

Module : $Header$

Description : Instance of class Logic for propositional logic

Copyright : (c) Dominik Luecke, Uni Bremen 2007

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

Maintainer : luecke@tzi.de

Stability : experimental

Portability : portable

Definition of symbols for propositional logic

-}

module Propositional.Symbol

(

Symbol (..) -- Symbol type

, pretty -- pretty printing for Symbols

, symOf -- Extracts the symbols out of a signature

, getSymbolMap -- Determines the symbol map

, getSymbolName -- Determines the name of a symbol

, idToRaw -- Creates a raw symbol

, symbolToRaw -- Convert symbol to raw symbol

, matches -- does a symbol match a raw symbol?

, applySymMap -- application function for symbol maps

) where

import qualified Common.Id as Id

import Common.Doc

import Common.DocUtils

import qualified Data.Set as Set

import qualified Data.Map as Map

import qualified Propositional.Sign as Sign

import qualified Propositional.Morphism as Morphism

-- | Datatype for symbols

newtype Symbol = Symbol {symName :: Id.Id}

deriving (Show, Eq, Ord)

instance Pretty Symbol where

pretty = printSymbol

printSymbol :: Symbol -> Doc

printSymbol x = pretty $ symName x

-- | Extraction of symbols from a signature

symOf :: Sign.Sign -> Set.Set Symbol

symOf x = Set.fold (\y -> Set.insert Symbol{symName = y}) Set.empty $

Sign.items x

-- | Determines the symbol map of a morhpism

getSymbolMap :: Morphism.Morphism -> Map.Map Symbol Symbol

getSymbolMap f = Map.foldWithKey

(\ k a -> Map.insert Symbol{symName=k} Symbol{symName=a})

Map.empty $ Morphism.propMap f

-- | Determines the name of a symbol

getSymbolName :: Symbol -> Id.Id

getSymbolName sym = symName sym

-- | make a raw_symbol

idToRaw :: Id.Id -> Symbol

idToRaw mid = Symbol {symName = mid}

-- | convert to raw symbol

symbolToRaw :: Symbol -> Symbol

symbolToRaw = id

-- | does a smybol match a raw symbol?

matches :: Symbol -> Symbol -> Bool

matches s1 s2 = s1 == s2

-- | application function for Symbol Maps

applySymMap :: Map.Map Symbol Symbol -> Symbol -> Symbol

applySymMap smap idt = Map.findWithDefault idt idt $ smap