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