From 845d5d286c34819057628dd8c3fafaf6e8578786 Mon Sep 17 00:00:00 2001
From: Maciek Makowski <maciek@mmakowski.com>
Date: Mon, 22 Mar 2004 17:42:27 +0000
Subject: [PATCH] Added extendDGraphRev function git-svn-id:
 https://svn-agbkb.informatik.uni-bremen.de/Hets/trunk@2305
 cec4b9c1-7d33-0410-9eda-942365e851bb

---
 Static/DevGraph.hs | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/Static/DevGraph.hs b/Static/DevGraph.hs
index 220e04b576..affc4eb839 100644
--- a/Static/DevGraph.hs
+++ b/Static/DevGraph.hs
@@ -172,7 +172,7 @@ extendDGraph :: DGraph    -- ^ the development graph to be extended
 	     -> Result (NodeSig, DGraph)
 -- ^ returns 1. the target signature of the morphism and 2. the resulting DGraph
 extendDGraph _ n@(EmptyNode _) _ _ =
-    do fatal_error "Trying to add a morphism originating from an empty node" nullPos
+    do fatal_error "Internal error: trying to add a morphism originating from an empty node" nullPos
 extendDGraph dg (NodeSig (n, G_sign lid _)) morph orig =
     let targetSig = cod Grothendieck morph
         nodeContents = DGNode {dgn_name = Nothing,
@@ -188,6 +188,31 @@ extendDGraph dg (NodeSig (n, G_sign lid _)) morph orig =
     in do return (NodeSig (node, targetSig), dg'')
 
 
+-- | Extend the development graph with given morphism pointing to 
+-- given NodeSig
+extendDGraphRev :: DGraph    -- ^ the development graph to be extended
+	     -> NodeSig   -- ^ the NodeSig to which the morphism points
+	     -> GMorphism -- ^ the morphism to be inserted
+	     -> DGOrigin  
+	     -> Result (NodeSig, DGraph)
+-- ^ returns 1. the source signature of the morphism and 2. the resulting DGraph
+extendDGraphRev _ n@(EmptyNode _) _ _ =
+    do fatal_error "Internal error: trying to add a morphism pointing to an empty node" nullPos
+extendDGraphRev dg (NodeSig (n, G_sign lid _)) morph orig =
+    let sourceSig = dom Grothendieck morph
+        nodeContents = DGNode {dgn_name = Nothing,
+			       dgn_sign = sourceSig,
+			       dgn_sens = G_l_sentence_list lid [],			       
+			       dgn_origin = orig}
+	linkContents = DGLink {dgl_morphism = morph,
+			       dgl_type = GlobalDef, -- TODO: other type
+			       dgl_origin = orig}
+	[node] = newNodes 0 dg
+	dg' = insNode (node, nodeContents) dg
+	dg'' = insEdge (node, n, linkContents) dg'
+    in do return (NodeSig (node, sourceSig), dg'')
+
+
 data ExtNodeSig = ExtNodeSig (Node,G_ext_sign) | ExtEmptyNode AnyLogic
                deriving (Eq,Show)