1 files changed, 123 insertions, 0 deletions
diff --git a/compiler/nstate.pas b/compiler/nstate.pas
new file mode 100644
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+++ b/compiler/nstate.pas
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+{
+    Copyright (c) 1998-2002 by Daniel Mantione
+
+    This unit contains support routines for the state tracker
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ ****************************************************************************
+}
+
+unit nstate;
+
+{$i fpcdefs.inc}
+
+interface
+
+uses    cclasses,node;
+
+type    Tstate_entry=class(Tlinkedlistitem)
+            what:Tnode;
+            value:Tnode;
+            constructor create(w,v:Tnode);
+        end;
+
+        Tstate_storage=class
+            storage:Tlinkedlist;
+            constructor create;
+            procedure store_fact(w,v:Tnode);
+            function find_fact(what:Tnode):Tnode;
+            procedure delete_fact(what:Tnode);
+        end;
+
+var     aktstate:Tstate_storage;
+
+implementation
+
+constructor Tstate_entry.create(w,v:Tnode);
+
+begin
+    inherited create;
+    what:=w;
+    value:=v;
+end;
+
+constructor Tstate_storage.create;
+
+begin
+    storage:=Tlinkedlist.create;
+end;
+
+procedure Tstate_storage.store_fact(w,v:Tnode);
+
+var se:Tstate_entry;
+
+begin
+{    writeln('fact:');
+    writenode(w);
+    writeln('=');
+    writenode(v);}
+    se:=Tstate_entry(storage.first);
+    while assigned(se) do
+        begin
+            if se.what.isequal(w) then
+                begin
+                    storage.remove(se);
+                    se.destroy;
+                    break;
+                end;
+            se:=Tstate_entry(se.next);
+        end;
+    se:=Tstate_entry.create(w,v);
+    storage.concat(se);
+end;
+
+function Tstate_storage.find_fact(what:Tnode):Tnode;
+
+var se:Tstate_entry;
+
+begin
+    find_fact:=nil;
+    se:=storage.first as Tstate_entry;
+    while assigned(se) do
+        begin
+            if se.what.isequal(what) then
+                begin
+                    find_fact:=se.value;
+                    break;
+                end;
+            se:=se.next as Tstate_entry;
+        end;
+end;
+
+procedure Tstate_storage.delete_fact(what:Tnode);
+
+var se:Tstate_entry;
+
+begin
+    se:=storage.first as Tstate_entry;
+    while assigned(se) do
+        begin
+            if se.what.isequal(what) then
+                begin
+                    storage.remove(se);
+                    se.destroy;
+                    break;
+                end;
+            se:=se.next as Tstate_entry;
+        end;
+end;
+
+end.