[Nice-commit] Nice/src/mlsub/typing/lowlevel Engine.java,1.26,1.27

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

Update of /cvsroot/nice/Nice/src/mlsub/typing/lowlevel
In directory sc8-pr-cvs1:/tmp/cvs-serv1807/src/mlsub/typing/lowlevel

Modified Files:
	Engine.java 
Log Message:
Made Object a super-type of every monotype.


Index: Engine.java
===================================================================
RCS file: /cvsroot/nice/Nice/src/mlsub/typing/lowlevel/Engine.java,v
retrieving revision 1.26
retrieving revision 1.27
diff -C2 -d -r1.26 -r1.27
*** Engine.java	2 Jun 2003 17:58:27 -0000	1.26
--- Engine.java	3 Dec 2003 21:50:41 -0000	1.27
***************
*** 204,208 ****
  
      Kind k1 = e1.getKind(), k2 = e2.getKind();
!     
      if(k1!=null)
        if(k2!=null)
--- 204,212 ----
  
      Kind k1 = e1.getKind(), k2 = e2.getKind();
! 
!     // If e2 is Top, this is trivial.
!     if (k2 == mlsub.typing.TopMonotype.TopKind.instance)
!       return;
! 
      if(k1!=null)
        if(k2!=null)
***************
*** 212,215 ****
--- 216,233 ----
  	  else
  	    {
+               /* If a non-rigid type variable was previously compared to some
+                  rigid element, it will have its type.
+                  it is still possible for it to be greater than Top
+                  (and therefore equal to Top). For this, we just need to
+                  forget its previous kind.
+               */
+               if (k1 == mlsub.typing.TopMonotype.TopKind.instance &&
+                   e2 instanceof mlsub.typing.MonotypeVar &&
+                   ! isRigid(e2))
+                 {
+                   ((mlsub.typing.MonotypeVar) e2).resetKind(k1);
+                   return;
+                 }
+ 
  	      if(dbg) 
  		Debug.println("Bad kinding discovered by Engine : "+
***************
*** 262,272 ****
      else
        {
! 	e.setId(-2); // for debugging purposes
  	floating.add(e);
        }
    }
    
    public static boolean isRigid(Element e)
    {
      Kind kind = e.getKind();
      if(kind==null)
--- 280,295 ----
      else
        {
! 	e.setId(FLOATING); // for debugging purposes
  	floating.add(e);
        }
    }
    
+   private static final int FLOATING = -3;
+ 
    public static boolean isRigid(Element e)
    {
+     if (e.getId() == FLOATING)
+       return false;
+ 
      Kind kind = e.getKind();
      if(kind==null)
***************
*** 387,390 ****
--- 410,415 ----
      throws Unsatisfiable
    {
+     boolean toTop = k == mlsub.typing.TopMonotype.TopKind.instance;
+ 
      Stack s = new Stack();
  
***************
*** 427,431 ****
  		  }
  	      else if(leq.e2==e)
! 		if(leq.e1.getKind()==null)
  		  s.push(leq.e1);
  		else
--- 452,459 ----
  		  }
  	      else if(leq.e2==e)
!                 // If e is Top, e1 <: e is trivial and can be discarded.
!                 if (toTop)
!                   i.remove();
!                 else if (leq.e1.getKind() == null)
  		  s.push(leq.e1);
  		else