{- |

Module : $Header$

Description : the proof status with manipulating functions

Copyright : (c) Jorina F. Gerken, Till Mossakowski, Uni Bremen 2002-2006

License : GPLv2 or higher, see LICENSE.txt

Maintainer : Christian.Maeder@dfki.de

Stability : provisional

Portability : non-portable(Logic)

the proof status with manipulating functions

-}

module Proofs.StatusUtils

( lookupHistory

, removeContraryChanges

, isIdentityEdge

) where

import Static.DevGraph

import Data.Graph.Inductive.Graph

import Common.LibName

import Logic.Logic

import qualified Common.Lib.SizedList as SizedList

import Data.List

{-

proof status = (DG0,[(R1,DG1),...,(Rn,DGn)])

DG0 is the development graph resulting from the static analysis

Ri is a list of rules that transforms DGi-1 to DGi

With the list of intermediate proof states, one can easily implement

an undo operation

-}

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

-- methods used in several proofs

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

{- returns the history that belongs to the given library name -}

lookupHistory :: LibName -> LibEnv -> ProofHistory

lookupHistory ln = clearHist . proofHistory . lookupDGraph ln

-- clear label lock

clr :: DGNodeLab -> DGNodeLab

clr l = l { dgn_lock = Nothing }

clearLock :: DGChange -> DGChange

clearLock c = case c of

InsertNode (n, l) -> InsertNode (n, clr l)

DeleteNode (n, l) -> InsertNode (n, clr l)

SetNodeLab o (n, l) -> SetNodeLab (clr o) (n, clr l)

_ -> c

clearHist :: ProofHistory -> ProofHistory

clearHist = SizedList.map clearElem

clearElem :: HistElem -> HistElem

clearElem e = case e of

HistElem c -> HistElem $ clearLock c

HistGroup r h -> HistGroup r $ clearHist h

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

-- methods that keep the change list clean

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

{- | remove the contray changes out of the list if it's necessary,

so that the list can stay clean.

-}

removeContraryChanges :: [DGChange] -> [DGChange]

removeContraryChanges cs = case cs of

[] -> []

c1 : r -> let recurse = c1 : removeContraryChanges r in case c1 of

SetNodeLab oldLbl (n, _) -> let

(r1, r2) = break (\ c2 -> case c2 of

SetNodeLab _ (m, _) -> n == m

DeleteNode (m, _) -> n == m

_ -> False) r

in case r2 of

[] -> recurse

c2 : r3 -> removeContraryChanges $ r1 ++ case c2 of

SetNodeLab _ (_, lbl) -> SetNodeLab oldLbl (n, lbl) : r3

DeleteNode _ -> DeleteNode (n, oldLbl) : r3

_ -> r2

InsertNode (n, _) -> let

(r1, r2) = break (\ c2 -> case c2 of

DeleteNode (m, _) -> n == m

_ -> False) r

(r1a, r1b) = partition (\ c2 -> case c2 of

SetNodeLab _ (m, _) -> n == m

_ -> False) r1

in case r2 of

[] -> case reverse r1a of

SetNodeLab _ (_, lbl) : _ ->

InsertNode (n, lbl) : removeContraryChanges r1b

_ -> recurse

_ : r3 -> removeContraryChanges $

filter (\ c2 -> case c2 of

InsertEdge (s, t, _) -> s /= n && t /= n

DeleteEdge (s, t, _) -> s /= n && t /= n

_ -> True) r1b ++ r3

DeleteNode (n, oldLbl) -> let

(r1, r2) = break (\ c2 -> case c2 of

InsertNode (m, _) -> n == m

_ -> False) r

in case r2 of

InsertNode (_, lbl) : r3 ->

removeContraryChanges $ r1 ++ SetNodeLab oldLbl (n, lbl) : r3

_ -> recurse

InsertEdge e1 -> let

(r1, r2) = break (\ c2 -> case c2 of

DeleteEdge e2 -> e1 == e2

_ -> False) r

in case r2 of

[] -> recurse

_ : r3 -> removeContraryChanges $ r1 ++ r3

DeleteEdge e1 -> let

(r1, r2) = break (\ c2 -> case c2 of

InsertEdge e2 -> e1 == e2

_ -> False) r

in case r2 of

[] -> recurse

_ : r3 -> removeContraryChanges $ r1 ++ r3

{- | check if the given edge is an identity edge, namely a loop

from a node to itself with an identity morphism. -}

isIdentityEdge :: LEdge DGLinkLab -> LibEnv -> DGraph -> Bool

isIdentityEdge (src, tgt, edgeLab) ps dgraph =

let nodeLab = labDG dgraph src

gsig = dgn_sign nodeLab

res = src == tgt &&

dgl_morphism edgeLab == ide gsig

in if isDGRef nodeLab then -- just a consistency check

let dg = lookupDGraph (dgn_libname nodeLab) ps

gsig2 = dgn_sign $ labDG dg $ dgn_node nodeLab

in if gsig2 == gsig then res else error "isIdentityEdge"

else res