{- |

Module : $Header$

Description : Heterogeneous colimit of the displayed graph

Copyright : (c) Mihai Codescu, and Uni Bremen 2002-2006

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

Maintainer : mcodescu@informatik.uni-bremen.de

Stability : provisional

Portability : non-portable

Computes the colimit and displays the graph after its insertion.

Improvements:

- error messages when the algorithm fails to compute

- insert edges just from a subset of nodes in the original graph

-}

module Proofs.ComputeColimit where

import Proofs.EdgeUtils

import Proofs.StatusUtils

import Static.DevGraph

import qualified Data.Map as Map

import Data.Graph.Inductive.Graph

import Syntax.AS_Library

import Common.Result

import Proofs.TheoremHideShift(makeDiagram)

computeColimit :: LIB_NAME -> LibEnv -> LibEnv

computeColimit ln le = let

dgraph = lookupDGraph ln le

(nextDGraph, nextHistoryElem) = insertColimitInGraph dgraph

in mkResultProofStatus ln le nextDGraph nextHistoryElem

insertColimitInGraph :: DGraph -> (DGraph,([DGRule],[DGChange]))

insertColimitInGraph dgraph = let

diag = makeDiagram dgraph (nodes $ dgBody dgraph) (labEdges $ dgBody dgraph)

in case maybeResult $ gWeaklyAmalgamableCocone diag of

Nothing -> (dgraph,([],[])) -- here not ok, see later

Just (gth, morFun) -> let

newNode = DGNodeLab{

dgn_name = emptyNodeName,

-- assign new name here, gn_Signature_Colimit?

dgn_theory = gth,

dgn_nf = Nothing,

dgn_sigma = Nothing,

nodeInfo = DGNode{

node_origin = DGProof,

node_cons = None,

node_cons_status = LeftOpen},

dgn_lock = error "uninitialized MVar of DGNode"}

newNodeNr = getNewNodeDG dgraph

edgeList = map (\n -> (n, newNodeNr,DGLink{

dgl_morphism = (Map.!)morFun n,

dgl_type = GlobalDef,

dgl_origin = DGProof,

dgl_id = defaultEdgeId})) $

nodes $ dgBody dgraph

--dgl_id field is filled when displayed

changes = [InsertNode (newNodeNr, newNode)] ++ map InsertEdge edgeList

(newGraph,newChanges) = updateWithChanges changes dgraph []

rules = [ComputeColimit]

in (newGraph, (rules,newChanges))