{- |

Module :

Copyright : (c) Cui Jian, Till Mossakowski, Uni Bremen 2002-2006

Description : simple version of theorem hide shift proof rule

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

Maintainer : ken@tzi.de

Stability : provisional

Portability : non-portable(Logic)

simple version of theorem hide shift proof rule for development graphs.

Follows Sect. IV:4.4 of the CASL Reference Manual.

-}

{-

References:

T. Mossakowski, S. Autexier and D. Hutter:

Extending Development Graphs With Hiding.

H. Hussmann (ed.): Fundamental Approaches to Software Engineering 2001,

Lecture Notes in Computer Science 2029, p. 269-283,

Springer-Verlag 2001.

-}

module Proofs.SimpleTheoremHideShift(theoremHideShift) where

import Static.DevGraph

import Syntax.AS_Library

import Proofs.EdgeUtils

import Static.DGToSpec

import Proofs.StatusUtils

import Data.Graph.Inductive.Graph

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

-- simplified theorem hide shift

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

-- | to be exported function

theoremHideShift :: LIB_NAME -> LibEnv -> LibEnv

theoremHideShift ln proofStatus =

let dgraph = lookupDGraph ln proofStatus

hidingDefEdges = filter (liftE isHidingDef) $ labEdges dgraph

(newDGraph, newHistory) =

theoremHideShiftFromList dgraph hidingDefEdges ([], [])

in mkResultProofStatus ln proofStatus newDGraph newHistory

-- | apply the theorem hide shift with a list of hiding definition links

theoremHideShiftFromList :: DGraph -> [LEdge DGLinkLab] -> ([DGRule], [DGChange]) -> (DGraph, ([DGRule], [DGChange]))

theoremHideShiftFromList dgraph [] history = (dgraph, history)

theoremHideShiftFromList dgraph ((e@(_, _, _)) : hidingDefEdges) history =

theoremHideShiftFromList newDGraph hidingDefEdges newHistory

where

(newDGraph, newChanges) = theoremHideShiftWithOneHidingDefEdge dgraph e

newHistory = if(not $ null newChanges) then (TheoremHideShift:(fst history), newChanges++(snd history))

else history

-- | apply the rule with one hiding definition link

theoremHideShiftWithOneHidingDefEdge :: DGraph -> LEdge DGLinkLab -> (DGraph, [DGChange])

theoremHideShiftWithOneHidingDefEdge dgraph e@(_, n, _) =

let

globalUnprovenEdges = getInComingGlobalUnprovenEdges dgraph n

in

theoremHideShiftWithOneHidingDefEdgeAux dgraph e globalUnprovenEdges []

-- | get all the global unproven threorem links which go into the given node in the given dgraph

getInComingGlobalUnprovenEdges :: DGraph -> Node -> [LEdge DGLinkLab]

getInComingGlobalUnprovenEdges dgraph n = filter ( \ (_, t, l) ->

t == n && isUnprovenGlobalThm (dgl_type l)) $ labEdges dgraph

-- | apply the rule to a list of global unproven threorem links with the related hiding definition link

theoremHideShiftWithOneHidingDefEdgeAux :: DGraph -> LEdge DGLinkLab -> [LEdge DGLinkLab] -> [DGChange] -> (DGraph, [DGChange])

theoremHideShiftWithOneHidingDefEdgeAux dgraph _ [] changes =

if(null changes) then (dgraph, changes)

else (dgraph, changes)

theoremHideShiftWithOneHidingDefEdgeAux dgraph (hd@(hds, _, _))

(x@(s, t, lbl) : xs) changes =

theoremHideShiftWithOneHidingDefEdgeAux finalDGraph hd xs finalChanges

where

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

-------- to insert an unproven global theorem link ------------

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

newMorphism = case calculateMorphismOfPath ([x,hd]) of

Just m -> m

Nothing -> error "Proofs.SimpleTheoremHideShift.theoremHideShiftWithOneHidingDefEdgeAux: could not compose two morphisms"

newGlobalEdge = (s,

hds,

DGLink {dgl_morphism = newMorphism,

dgl_type = (GlobalThm LeftOpen

None LeftOpen),

dgl_origin = DGProof}

)

(newDGraph, newChanges) = tryToInsertEdge dgraph newGlobalEdge changes

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

-------- to insert a proven global theorem link ---------------

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

(GlobalThm _ conservativity conservStatus) = dgl_type lbl

proofBasis = [newGlobalEdge] --selectProof newDGraph x [[]]

provenEdge = (

s,

t,

DGLink {

dgl_morphism = dgl_morphism lbl,

dgl_type = (GlobalThm (Proven TheoremHideShift proofBasis) conservativity conservStatus),

dgl_origin = DGProof

}

)

(newDGraph2, newChanges2) = tryToInsertEdge newDGraph provenEdge newChanges

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

-------- delete the being processed unproven global theorem link ---------------

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

(finalDGraph, finalChanges) = (deLLEdge x newDGraph2, (DeleteEdge x):newChanges2)

-- | try to insert an edge to the given dgraph. If the to be inserted edge exists, do nothing ;)

tryToInsertEdge :: DGraph -> LEdge DGLinkLab -> [DGChange] -> (DGraph, [DGChange])

tryToInsertEdge dgraph newEdge changes =

case isDuplicate newEdge dgraph changes of

True -> (dgraph, changes)

False -> ((insEdge newEdge dgraph), (InsertEdge newEdge):changes)