GNU Prolog for Java

gnu.prolog.vm
Class BacktrackInfo

java.lang.Object
  extended by gnu.prolog.vm.BacktrackInfo
Direct Known Subclasses:
CallBacktrackInfo, EnterBacktrackInfo, LeaveBacktrackInfo, LeaveByteCodeBacktrackInfo, Predicate_append.AppendBacktrackInfo, Predicate_call.CallTermBacktrackInfo, Predicate_member.MemberBacktrackInfo, PrologCollectionIterator, RetryBacktrackInfo

public class BacktrackInfo
extends Object

back track information base class


Field Summary
 int codePosition
          A pointer to code position.
 int undoPosition
          A position in undo stack.
 
Constructor Summary
BacktrackInfo(int undoPosition, int codePosition)
          a constructor
 
Method Summary
 void undo(Interpreter i)
          undo changes up to creation of this backtrack info
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

codePosition

public int codePosition
A pointer to code position. This pointer is interpreted by function that created backtrack information. TODO: what is the meaning of -1 here?


undoPosition

public int undoPosition
A position in undo stack. all actions will be undone up to this position. TODO: what is the meaning of -1 here?

Constructor Detail

BacktrackInfo

public BacktrackInfo(int undoPosition,
                     int codePosition)
a constructor

Parameters:
undoPosition - undoPosition
codePosition - codePosition
Method Detail

undo

public void undo(Interpreter i)
undo changes up to creation of this backtrack info


GNU Prolog for Java