--- a/src/pt-exp.cc	Thu May 15 22:36:40 1997 +0000
+++ b/src/pt-exp.cc	Fri May 16 01:13:19 1997 +0000
@@ -28,971 +28,65 @@
 #include <config.h>
 #endif
 
+#include <string>
+
 #include <iostream.h>
 #include <strstream.h>
 
-#include "defun.h"
 #include "error.h"
-#include "gripes.h"
-#include "help.h"
-#include "input.h"
-#include "oct-obj.h"
+#include "pager.h"
 #include "oct-lvalue.h"
-#include "pager.h"
 #include "ov.h"
 #include "pt-exp.h"
-#include "pt-id.h"
-#include "pt-indir.h"
-#include "pt-misc.h"
-#include "pt-pr-code.h"
-#include "pt-walk.h"
-#include "utils.h"
-#include "variables.h"
 
-// Nonzero means we're returning from a function.
-extern int returning;
-
-// Nonzero means we're breaking out of a loop or function body.
-extern int breaking;
-
-// TRUE means print the right hand side of an assignment instead of
-// the left.
-static bool Vprint_rhs_assign_val;
-
-// Prefix expressions.
-
-octave_value_list
-tree_prefix_expression::rvalue (int nargout)
-{
-  octave_value_list retval;
-
-  if (nargout > 1)
-    error ("prefix operator `%s': invalid number of output arguments",
-	   oper () . c_str ());
-  else
-    retval = rvalue ();
-
-  return retval;
-}
-
-octave_value
-tree_prefix_expression::rvalue (void)
-{
-  octave_value retval;
-
-  if (error_state)
-    return retval;
-
-  if (op)
-    {
-      if (etype == unot || etype == uminus)
-	{
-	  octave_value val = op->rvalue ();
-
-	  if (! error_state)
-	    {
-	      if (val.is_defined ())
-		{
-		  if (etype == unot)
-		    retval = val.not ();
-		  else
-		    retval = val.uminus ();
-		}
-	      else
-		error ("argument to prefix operator `%s' undefined",
-		       oper () . c_str ());
-	    }
-	}
-      else if (etype == increment || etype == decrement)
-	{
-	  octave_lvalue ref = op->lvalue ();
+// Expressions.
 
-	  if (! error_state)
-	    {
-	      if (ref.is_defined ())
-		{
-		  if (etype == increment)
-		    ref.increment ();
-		  else
-		    ref.decrement ();
-
-		  retval = ref.value ();
-		}
-	      else
-		error ("argument to prefix operator `%s' undefined",
-		       oper () . c_str ());
-	    }
-	}
-      else
-	error ("prefix operator %d not implemented", etype);
-    }
-
-  return retval;
-}
-
-void
-tree_prefix_expression::eval_error (void)
-{
-  if (error_state > 0)
-    ::error ("evaluating prefix operator `%s' near line %d, column %d",
-	     oper () . c_str (), line (), column ());
-}
-
-string
-tree_prefix_expression::oper (void) const
+bool
+tree_expression::is_logically_true (const char *warn_for)
 {
-  string retval = "<unknown>";
-
-  switch (etype)
-    {
-    case unot:
-      retval = "!";
-      break;
-
-    case uminus:
-      retval = "-";
-      break;
-
-    case increment:
-      retval = "++";
-      break;
-
-    case decrement:
-      retval = "--";
-      break;
-
-    default:
-      break;
-    }
-
-  return retval;
-}
-
-void
-tree_prefix_expression::accept (tree_walker& tw)
-{
-  tw.visit_prefix_expression (*this);
-}
-
-// Postfix expressions.
-
-octave_value_list
-tree_postfix_expression::rvalue (int nargout)
-{
-  octave_value_list retval;
-
-  if (nargout > 1)
-    error ("postfix operator `%s': invalid number of output arguments",
-	   oper () . c_str ());
-  else
-    retval = rvalue ();
-
-  return retval;
-}
+  bool expr_value = false;
 
-octave_value
-tree_postfix_expression::rvalue (void)
-{
-  octave_value retval;
-
-  if (error_state)
-    return retval;
-
-  if (op)
-    {
-      if (etype == transpose || etype == hermitian)
-	{
-	  octave_value val = op->rvalue ();
-
-	  if (! error_state)
-	    {
-	      if (val.is_defined ())
-		{
-		  if (etype == transpose)
-		    retval = val.transpose ();
-		  else
-		    retval = val.hermitian ();
-		}
-	      else
-		error ("argument to postfix operator `%s' undefined",
-		       oper () . c_str ());
-	    }
-	}
-      else if (etype == increment || etype == decrement)
-	{
-	  octave_lvalue ref = op->lvalue ();
-
-	  if (! error_state)
-	    {
-	      if (ref.is_defined ())
-		{
-		  retval = ref.value ();
-
-		  if (etype == increment)
-		    ref.increment ();
-		  else
-		    ref.decrement ();
-		}
-	      else
-		error ("argument to postfix operator `%s' undefined",
-		       oper () . c_str ());
-	    }
-	}
-      else
-	error ("postfix operator %d not implemented", etype);
-    }
-
-  return retval;
-}
-
-void
-tree_postfix_expression::eval_error (void)
-{
-  if (error_state > 0)
-    ::error ("evaluating postfix operator `%s' near line %d, column %d",
-	     oper () . c_str (), line (), column ());
-}
-
-string
-tree_postfix_expression::oper (void) const
-{
-  string retval = "<unknown>";
-
-  switch (etype)
-    {
-    case transpose:
-      retval = ".'";
-      break;
+  octave_value t1 = rvalue ();
 
-    case hermitian:
-      retval = "'";
-      break;
-
-    case increment:
-      retval = "++";
-      break;
-
-    case decrement:
-      retval = "--";
-      break;
-
-    default:
-      break;
-    }
-
-  return retval;
-}
-
-void
-tree_postfix_expression::accept (tree_walker& tw)
-{
-  tw.visit_postfix_expression (*this);
-}
-
-// Binary expressions.
- 
-octave_value_list
-tree_binary_expression::rvalue (int nargout)
-{
-  octave_value_list retval;
-
-  if (nargout > 1)
-    error ("binary operator `%s': invalid number of output arguments",
-	   oper () . c_str ());
-  else
-    retval = rvalue ();
-
-  return retval;
-}
-
-octave_value
-tree_binary_expression::rvalue (void)
-{
-  octave_value retval;
-
-  if (error_state)
-    return retval;
-
-  if (op_lhs)
+  if (! error_state)
     {
-      octave_value a = op_lhs->rvalue ();
-
-      if (error_state)
-	eval_error ();
-      else if (a.is_defined () && op_rhs)
-	{
-	  octave_value b = op_rhs->rvalue ();
-
-	  if (error_state)
-	    eval_error ();
-	  else if (b.is_defined ())
-	    {
-	      retval = ::do_binary_op (etype, a, b);
-
-	      if (error_state)
-		{
-		  retval = octave_value ();
-		  eval_error ();
-		}
-	    }
-	  else
-	    eval_error ();
-	}
+      if (t1.is_defined ())
+	return t1.is_true ();
       else
-	eval_error ();
+	::error ("%s: undefined value used in conditional expression",
+		 warn_for);
     }
   else
-    eval_error ();
-
-  return retval;
-}
-
-void
-tree_binary_expression::eval_error (void)
-{
-  if (error_state > 0)
-    ::error ("evaluating binary operator `%s' near line %d, column %d",
-	     oper () . c_str (), line (), column ());
-}
-
-string
-tree_binary_expression::oper (void) const
-{
-  return octave_value::binary_op_as_string (etype);
-}
-
-void
-tree_binary_expression::accept (tree_walker& tw)
-{
-  tw.visit_binary_expression (*this);
-}
-
-// Boolean expressions.
- 
-octave_value_list
-tree_boolean_expression::rvalue (int nargout)
-{
-  octave_value_list retval;
-
-  if (nargout > 1)
-    error ("binary operator `%s': invalid number of output arguments",
-	   oper () . c_str ());
-  else
-    retval = rvalue ();
-
-  return retval;
-}
-
-octave_value
-tree_boolean_expression::rvalue (void)
-{
-  octave_value retval;
-
-  if (error_state)
-    return retval;
-
-  bool result = false;
-
-  if (op_lhs)
-    {
-      octave_value a = op_lhs->rvalue ();
-
-      if (error_state)
-	eval_error ();
-      else
-	{
-	  bool a_true = a.is_true ();
+    ::error ("%s: error evaluating conditional expression", warn_for);
 
-	  if (error_state)
-	    eval_error ();
-	  else
-	    {
-	      if (a_true)
-		{
-		  if (etype == bool_or)
-		    {
-		      result = true;
-		      goto done;
-		    }
-		}
-	      else
-		{
-		  if (etype == bool_and)
-		    goto done;
-		}
-
-	      if (op_rhs)
-		{
-		  octave_value b = op_rhs->rvalue ();
-
-		  if (error_state)
-		    eval_error ();
-		  else
-		    {
-		      result = b.is_true ();
-
-		      if (error_state)
-			eval_error ();
-		    }
-		}
-	      else
-		eval_error ();
-
-	    done:
-
-	      if (! error_state)
-		retval = octave_value (static_cast<double> (result));
-	    }
-	}
-    }
-  else
-    eval_error ();
-
-  return retval;
-}
-
-string
-tree_boolean_expression::oper (void) const
-{
-  string retval = "<unknown>";
-
-  switch (etype)
-    {
-    case bool_and:
-      retval = "&&";
-      break;
-
-    case bool_or:
-      retval = "||";
-      break;
-
-    default:
-      break;
-    }
-
-  return retval;
-}
-
-// Simple assignment expressions.
-
-tree_simple_assignment::~tree_simple_assignment (void)
-{
-  if (! preserve)
-    delete lhs;
-
-  delete rhs;
-}
-
-octave_value_list
-tree_simple_assignment::rvalue (int nargout)
-{
-  octave_value_list retval;
-
-  if (nargout > 1)
-    error ("invalid number of output arguments for expression X = RHS");
-  else
-    retval = rvalue ();
-
-  return retval;
+  return expr_value;
 }
 
 octave_value
-tree_simple_assignment::rvalue (void)
-{
-  octave_value rhs_val;
-
-  if (error_state)
-    return rhs_val;
-
-  if (rhs)
-    {
-      octave_value_list tmp = rhs->rvalue ();
-
-      if (! (error_state || tmp.empty ()))
-	{
-	  rhs_val = tmp(0);
-
-	  if (rhs_val.is_undefined ())
-	    {
-	      error ("value on right hand side of assignment is undefined");
-	      eval_error ();
-	    }
-	  else
-	    {
-	      octave_lvalue ult = lhs->lvalue ();
-
-	      if (error_state)
-		eval_error ();
-	      else
-		{
-		  ult.assign (etype, rhs_val);
-
-		  if (error_state)
-		    eval_error ();
-		  else if (! Vprint_rhs_assign_val)
-		    {
-		      octave_value lhs_val = ult.value ();
-
-		      if (! error_state && print_result ())
-			{
-			  if (Vprint_rhs_assign_val)
-			    {
-			      ostrstream buf;
-
-			      tree_print_code tpc (buf);
-
-			      lhs->accept (tpc);
-
-			      buf << ends;
-
-			      const char *tag = buf.str ();
-
-			      rhs_val.print_with_name (octave_stdout, tag);
-
-			      delete [] tag;
-			    }
-			  else
-			    lhs_val.print_with_name (octave_stdout,
-						     lhs->name ());
-			}
-		    }
-		}
-	    }
-	}
-      else
-	eval_error ();
-    }
-
-  return rhs_val;
-}
-
-void
-tree_simple_assignment::eval_error (void)
-{
-  if (error_state > 0)
-    {
-      int l = line ();
-      int c = column ();
-
-      if (l != -1 && c != -1)
-	::error ("evaluating assignment expression near line %d, column %d",
-		 l, c);
-    }
-}
-
-string
-tree_simple_assignment::oper (void) const
-{
-  return octave_value::assign_op_as_string (etype);
-}
-
-void
-tree_simple_assignment::accept (tree_walker& tw)
-{
-  tw.visit_simple_assignment (*this);
-}
-
-// Colon expressions.
-
-tree_colon_expression *
-tree_colon_expression::append (tree_expression *t)
+tree_expression::rvalue (void)
 {
-  tree_colon_expression *retval = 0;
-
-  if (op_base)
-    {
-      if (op_limit)
-	{
-	  if (op_increment)
-	    ::error ("invalid colon expression");
-	  else
-	    {
-	      // Stupid syntax:
-	      //
-	      // base : limit
-	      // base : increment : limit
-
-	      op_increment = op_limit;
-	      op_limit = t;
-	    }
-	}
-      else
-	op_limit = t;
-
-      retval = this;
-    }
-  else
-    ::error ("invalid colon expression");
-
-  return retval;
-}
-
-octave_value_list
-tree_colon_expression::rvalue (int nargout)
-{
-  octave_value_list retval;
-
-  if (nargout > 1)
-    error ("invalid number of output arguments for colon expression");
-  else
-    retval = rvalue ();
-
-  return retval;
-}
-
-octave_value
-tree_colon_expression::rvalue (void)
-{
-  octave_value retval;
-
-  if (error_state || ! op_base || ! op_limit)
-    return retval;
-
-  octave_value tmp = op_base->rvalue ();
-
-  if (tmp.is_undefined ())
-    {
-      eval_error ("invalid null value in colon expression");
-      return retval;
-    }
-
-  double xbase = tmp.double_value ();
-
-  if (error_state)
-    {
-      eval_error ("colon expression elements must be scalars");
-      return retval;
-    }
-
-  tmp = op_limit->rvalue ();
-
-  if (tmp.is_undefined ())
-    {
-      eval_error ("invalid null value in colon expression");
-      return retval;
-    }
-
-  double xlimit = tmp.double_value ();
-
-  if (error_state)
-    {
-      eval_error ("colon expression elements must be scalars");
-      return retval;
-    }
-
-  double xinc = 1.0;
-
-  if (op_increment)
-    {
-      tmp = op_increment->rvalue ();
-
-      if (tmp.is_undefined ())
-	{
-	  eval_error ("invalid null value in colon expression");
-	  return retval;
-	}
-
-      xinc = tmp.double_value ();
-
-      if (error_state)
-	{
-	  eval_error ("colon expression elements must be scalars");
-	  return retval;
-	}
-    }
-
-  retval = octave_value (xbase, xlimit, xinc);
-
-  if (error_state)
-    {
-      if (error_state)
-	eval_error ();
-
-      return octave_value ();
-    }
-
-  return retval;
-}
-
-void
-tree_colon_expression::eval_error (const string& s)
-{
-  if (error_state > 0)
-    {
-      if (! s.empty ())
-	::error ("%s", s.c_str ());
-
-      ::error ("evaluating colon expression near line %d column %d",
-	       line (), column ());
-    }
-}
-
-void
-tree_colon_expression::accept (tree_walker& tw)
-{
-  tw.visit_colon_expression (*this);
-}
-
-tree_index_expression::~tree_index_expression (void)
-{
-  delete expr;
-  delete list;
+  ::error ("invalid rvalue function called in expression");
+  return octave_value ();
 }
 
 octave_value_list
-tree_index_expression::rvalue (int nargout)
+tree_expression::rvalue (int nargout)
 {
-  octave_value_list retval;
-
-  if (error_state)
-    return retval;
-
-  octave_value tmp = expr->rvalue ();
-
-  if (! error_state)
-    {
-      octave_value_list args;
-
-      if (list)
-	args = list->convert_to_const_vector ();
-
-      if (! error_state)
-	{
-	  if (! args.empty ())
-	    args.stash_name_tags (arg_nm);
-
-	  // XXX FIXME XXX -- is this the right thing to do?
-	  if (tmp.is_constant ())
-	    retval = tmp.do_index_op (args);
-	  else
-	    retval = tmp.do_index_op (nargout, args);
-	}
-      else
-	eval_error ();
-    }
-  else
-    eval_error ();
-
-  return retval;
-}
-
-octave_value
-tree_index_expression::rvalue (void)
-{
-  octave_value retval;
-
-  octave_value_list tmp = rvalue (1);
-
-  if (! tmp.empty ())
-    retval = tmp(0);
-
-  return retval;
+  ::error ("invalid rvalue function called in expression");
+  return octave_value_list ();
 }
 
 octave_lvalue
-tree_index_expression::lvalue (void)
-{
-  octave_lvalue retval;
-
-  if (! error_state)
-    {
-      retval = expr->lvalue ();
-
-      if (! error_state)
-	{
-	  octave_value_list args;
-	  
-	  if (list)
-	    args = list->convert_to_const_vector ();
-
-	  retval.index (args);
-	}
-    }
-
-  return retval;
-}
-
-void
-tree_index_expression::eval_error (void)
+tree_expression::lvalue (void)
 {
-  if (error_state > 0)
-    {
-      int l = line ();
-      int c = column ();
-
-      if (l != -1 && c != -1)
-	{
-	  if (list)
-	    ::error ("evaluating index expression near line %d, column %d",
-		     l, c);
-	  else
-	    ::error ("evaluating expression near line %d, column %d", l, c);
-	}
-      else
-	{
-	  if (list)
-	    ::error ("evaluating index expression");
-	  else
-	    ::error ("evaluating expression");
-	}
-    }
-}
-
-void
-tree_index_expression::accept (tree_walker& tw)
-{
-  tw.visit_index_expression (*this);
-}
-
-tree_multi_assignment::~tree_multi_assignment (void)
-{
-  if (! preserve)
-    delete lhs;
-
-  delete rhs;
-}
-
-octave_value
-tree_multi_assignment::rvalue (void)
-{
-  octave_value retval;
-
-  octave_value_list tmp = rvalue (1);
-
-  if (! tmp.empty ())
-    retval = tmp(0);
-
-  return retval;
+  ::error ("invalid lvalue function called in expression");
+  return octave_lvalue ();
 }
 
-octave_value_list
-tree_multi_assignment::rvalue (int nargout)
+string
+tree_expression::original_text (void) const
 {
-  octave_value_list rhs_val;
-
-  if (error_state)
-    return rhs_val;
-
-  if (rhs)
-    {
-      int n_out = lhs->length ();
-
-      rhs_val = rhs->rvalue (n_out);
-
-      if (! (error_state || rhs_val.empty ()))
-	{
-	  if (rhs_val.empty ())
-	    {
-	      error ("value on right hand side of assignment is undefined");
-	      eval_error ();
-	    }
-	  else
-	    {
-	      int k = 0;
-
-	      int n = rhs_val.length ();
-
-	      for (Pix p = lhs->first (); p != 0; lhs->next (p))
-		{
-		  tree_expression *lhs_elt = lhs->operator () (p);
-
-		  if (lhs_elt)
-		    {
-		      octave_lvalue ult = lhs_elt->lvalue ();
-
-		      if (error_state)
-			eval_error ();
-		      else
-			{
-			  octave_value tmp = k < n
-			    ? rhs_val(k++) : octave_value ();
-
-			  if (tmp.is_defined ())
-			    {
-			      // XXX FIXME XXX -- handle other assignment ops.
-			      ult.assign (octave_value::asn_eq, tmp);
-			    }
-			  else
-			    error ("element number %d undefined in return list", k);
-
-			  if (error_state)
-			    eval_error ();
-			  else if (! Vprint_rhs_assign_val)
-			    {
-			      octave_value lhs_val = ult.value ();
-
-			      if (! error_state && print_result ())
-				{
-				  if (Vprint_rhs_assign_val)
-				    {
-				      ostrstream buf;
-
-				      tree_print_code tpc (buf);
-
-				      lhs_elt->accept (tpc);
-
-				      buf << ends;
-
-				      const char *tag = buf.str ();
-
-				      tmp.print_with_name
-					(octave_stdout, tag);
-
-				      delete [] tag;
-				    }
-				  else
-				    lhs_val.print_with_name (octave_stdout,
-							     lhs_elt->name ());
-				}
-			    }
-			}
-		    }
-
-		  if (error_state)
-		    break;
-		}
-	    }
-	}
-      else
-	eval_error ();
-    }
-
-  return rhs_val;
-}
-
-void
-tree_multi_assignment::eval_error (void)
-{
-  if (error_state > 0)
-    {
-      int l = line ();
-      int c = column ();
-
-      if (l != -1 && c != -1)
-	::error ("evaluating assignment expression near line %d, column %d",
-		 l, c);
-    }
-}
-
-void
-tree_multi_assignment::accept (tree_walker& tw)
-{
-  tw.visit_multi_assignment (*this);
-}
-
-static int
-print_rhs_assign_val (void)
-{
-  Vprint_rhs_assign_val = check_preference ("print_rhs_assign_val");
-
-  return 0;
-}
-
-void
-symbols_of_pt_exp (void)
-{
-  DEFVAR (print_rhs_assign_val, 0.0, 0, print_rhs_assign_val,
-    "if TRUE, print the right hand side of assignments instead of the left");
+  return string ();
 }
 
 /*