[Nice-commit] Nice/src/mlsub/typing/lowlevel K0.java,1.20,1.21 Engine.java,1.30,1.31

[Daniel B. <bo...@us...>]

Update of /cvsroot/nice/Nice/src/mlsub/typing/lowlevel
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv24136/src/mlsub/typing/lowlevel

Modified Files:
	K0.java Engine.java 
Log Message:
When doing overloading resolution in existential mode, backtrack when the
symbol is not applicable.


Index: K0.java
===================================================================
RCS file: /cvsroot/nice/Nice/src/mlsub/typing/lowlevel/K0.java,v
retrieving revision 1.20
retrieving revision 1.21
diff -C2 -d -r1.20 -r1.21
*** K0.java	11 Sep 2003 20:01:03 -0000	1.20
--- K0.java	23 Mar 2004 20:28:43 -0000	1.21
***************
*** 1371,1375 ****
  
    // backtrack to the situation the last time mark() has been called
!   public void backtrack() {
      if (backup == null)
        // This can happen for a K0 that has been created on the fly
--- 1371,1375 ----
  
    // backtrack to the situation the last time mark() has been called
!   public void backtrack(boolean ignore) {
      if (backup == null)
        // This can happen for a K0 that has been created on the fly
***************
*** 1377,1380 ****
--- 1377,1386 ----
        return;
  
+     if (ignore)
+       {
+         backup = backup.previous;
+         return;
+       }
+ 
      S.assume(S.a&& hasBeenInitialized);
  
***************
*** 2133,2137 ****
              possibilities.clear(x0);
            } finally {
!             backtrack();
              backup = savedBackup;
            }
--- 2139,2143 ----
              possibilities.clear(x0);
            } finally {
!             backtrack(false);
              backup = savedBackup;
            }

Index: Engine.java
===================================================================
RCS file: /cvsroot/nice/Nice/src/mlsub/typing/lowlevel/Engine.java,v
retrieving revision 1.30
retrieving revision 1.31
diff -C2 -d -r1.30 -r1.31
*** Engine.java	23 Mar 2004 14:45:21 -0000	1.30
--- Engine.java	23 Mar 2004 20:28:43 -0000	1.31
***************
*** 38,49 ****
     * a matching leave() MUST be issued some time later by the caller.
     */
!   public static void enter()
    {
      if(dbg) Debug.println("Enter");
      floating.mark();
      soft.mark();
  
      // Once we are in existential mode, we don't mark/backtrack.
!     if (existentialLevel > 0)
        existentialLevel++;
      else
--- 38,50 ----
     * a matching leave() MUST be issued some time later by the caller.
     */
!   public static void enter(boolean tentative)
    {
      if(dbg) Debug.println("Enter");
      floating.mark();
      soft.mark();
+     formerFree.mark();
  
      // Once we are in existential mode, we don't mark/backtrack.
!     if (!tentative && existentialLevel > 0)
        existentialLevel++;
      else
***************
*** 102,108 ****
     * @exception Unsatisfiable if the constraint was not satisfiable.
     */
!   public static void leave()
      throws Unsatisfiable
    {
      try{
        assertFrozens();
--- 103,115 ----
     * @exception Unsatisfiable if the constraint was not satisfiable.
     */
!   public static void leave(boolean tentative, boolean commit)
      throws Unsatisfiable
    {
+     // 'tentative' is only meaningful when in existential mode
+     tentative &= existentialLevel > 0;
+     // We only 'commit' in tentative mode
+     commit &= tentative;
+       
+     boolean ok = false;
      try{
        assertFrozens();
***************
*** 125,137 ****
  	  }
  	}
      }
      finally{
!       backtrack();
      }
    }
    
!   public static void backtrack()
    {
!     if (existentialLevel <= 1)
        {
          for(Iterator i = constraints.iterator();
--- 132,149 ----
  	  }
  	}
+       ok = true;
      }
      finally{
!       // Even if commit is true, if an error appeared during leaving
!       // then we don't want to keep the changes.
!       backtrack(tentative, ok && commit);
      }
    }
    
!   public static void backtrack(boolean tentative, boolean commit)
    {
!     floating.backtrack();
! 
!     if (existentialLevel <= 1 || tentative)
        {
          for(Iterator i = constraints.iterator();
***************
*** 139,152 ****
            { 
              Engine.Constraint k = (Engine.Constraint) i.next();
!             k.backtrack();
            }
  
!         frozenLeqs.backtrack();
        }
  
-     floating.backtrack();
      soft.backtrack();
  
!     if (existentialLevel > 0)
        existentialLevel--;
    }
--- 151,182 ----
            { 
              Engine.Constraint k = (Engine.Constraint) i.next();
!             k.backtrack(commit);
            }
  
!         if (! commit)
!           frozenLeqs.backtrack();
! 
!         if (tentative && !commit)
!           {
!             // These type variables used to be free. Since we don't commit, 
!             // we must set them free again!
!             try{
!               for (Iterator i = formerFree.iterator(); i.hasNext();)
!                 {
!                   Element e = (Element) i.next();
!                   e.setKind(null);
!                   floating.add(e);
!                 }
!             }
!             finally{
!               formerFree.endOfIteration();
!             }
!           }
        }
  
      soft.backtrack();
+     formerFree.backtrack();
  
!     if (!tentative && existentialLevel > 0)
        existentialLevel--;
    }
***************
*** 451,454 ****
--- 481,487 ----
  	       "\nnew: " + k);
  	
+         if (e.isExistential())
+           formerFree.add(e);
+ 
  	// assert e.getKind()==null
  	k.register(e);
***************
*** 616,619 ****
--- 649,653 ----
  	  e.setKind(variablesConstraint);
  	  variablesConstraint.register(e);
+           i.remove();
  	}
      }
***************
*** 621,625 ****
        floating.endOfIteration();
      }
-     floating.clear();
      
      try {
--- 655,658 ----
***************
*** 685,688 ****
--- 718,724 ----
    private static final BackableList soft = new BackableList();
    
+   /** The elements that have been put into a kind since the last mark. */
+   private static final BackableList formerFree = new BackableList();
+   
    /** The constraint of monotype variables */
    public static Engine.Constraint variablesConstraint;
***************
*** 960,966 ****
      }
  
!     void backtrack()
      {
!       k0.backtrack();
      }
  
--- 996,1002 ----
      }
  
!     void backtrack(boolean ignore)
      {
!       k0.backtrack(ignore);
      }