# HG changeset patch
# User jwe
# Date 1150174771 0
# Node ID 92d2be71e7cc0cb292e8c67d467479775eb6e8b9
# Parent  68f8017ef07717f137e10d588d2abb5b15af0de3
[project @ 2006-06-13 04:59:30 by jwe]

diff --git a/src/ChangeLog b/src/ChangeLog
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2006-06-13  John W. Eaton  <jwe@octave.org>
+
+	* pt-stmt.cc (tree_statement_list::eval):
+	Clear retval before each statement is evaluated.
+
 2006-06-12  John W. Eaton  <jwe@octave.org>
 
 	* unwind-prot.h (unwind_protect_fptr): New macro.
diff --git a/src/pt-stmt.cc b/src/pt-stmt.cc
--- a/src/pt-stmt.cc
+++ b/src/pt-stmt.cc
@@ -165,6 +165,17 @@
 	{
 	  OCTAVE_QUIT;
 
+	  // Clear preivous values before next statement is evaluated
+	  // so that we aren't holding an extra reference to a value
+	  // that may be used next.  For example, in code like this:
+	  //
+	  //   X = rand (N);  ## refcount should be 1 after this statement.
+	  //   X(idx) = val;  ## no extra copy should be needed, but
+	  //                  ## we will be faked out if retval is not
+	  //                  ## cleared between statements here.
+
+	  retval = octave_value_list ();
+
 	  retval = elt->eval (silent, nargout, function_body);
 
 	  if (error_state)
@@ -179,8 +190,6 @@
 	}
       else
 	error ("invalid statement found in statement list!");
-
-
     }
 
   return retval;