begin refactoring parse tree evaluator * libinterp/parse-tree/pt-tm-const.cc, libinterp/parse-tree/pt-tm-const.h: New files, extracted from pt-mat.h and pt-mat.cc. * libinterp/parse-tree/module.mk: Update. * interpreter.cc, ov-class.cc, ov-classdef.cc, ov-classdef.h, ov-fcn-handle.cc, ov-fcn-handle.h, ov-usr-fcn.cc, oct-parse.in.yy, pt-arg-list.cc, pt-arg-list.h, pt-array-list.h, pt-assign.cc, pt-assign.h, pt-binop.cc, pt-binop.h, pt-cbinop.cc, pt-cbinop.h, pt-cell.cc, pt-cell.h, pt-classdef.cc, pt-classdef.h, pt-cmd.cc, pt-cmd.h, pt-colon.cc, pt-colon.h, pt-const.cc, pt-const.h, pt-decl.cc, pt-decl.h, pt-eval.cc, pt-eval.h, pt-except.cc, pt-except.h, pt-exp.cc, pt-exp.h, pt-fcn-handle.cc, pt-fcn-handle.h, pt-funcall.cc, pt-funcall.h, pt-id.cc, pt-id.h, pt-idx.cc, pt-idx.h, pt-jit.cc, pt-jump.cc, pt-jump.h, pt-loop.cc, pt-loop.h, pt-mat.cc, pt-mat.h, pt-misc.cc, pt-misc.h, pt-select.cc, pt-select.h, pt-stmt.cc, pt-stmt.h, pt-unop.cc, pt-unop.h: Use tree_evaluator class to walk the parse tree instead of rvalue methods in the parse tree classes. Maintain a stack in the evaluator class to accumulate results. Pass pointer to evaluator to function objects and other classes as needed for evaluation. This is a work in progress that is not yet complete. The ultimate goal is to move all evaluation into the tree_evaluator class instead of spreading that work among many different classes. The global pointer to the current evaluator should also be eliminated.

--- a/libinterp/parse-tree/pt-id.h	Mon Apr 24 21:03:38 2017 -0700
+++ b/libinterp/parse-tree/pt-id.h	Fri Apr 21 18:07:40 2017 -0400
@@ -35,11 +35,12 @@
 #include "oct-lvalue.h"
 #include "pt-bp.h"
 #include "pt-exp.h"
+#include "pt-walk.h"
 #include "symtab.h"
 
 namespace octave
 {
-  class tree_walker;
+  class tree_evaluator;
 
   // Symbols from the symbol table.
 
@@ -111,17 +112,7 @@
 
     bool lvalue_ok (void) const { return true; }
 
-    octave_value rvalue1 (int nargout = 1);
-
-    octave_value_list rvalue (int nargout)
-    {
-      return rvalue (nargout, 0);
-    }
-
-    octave_value_list rvalue (int nargout,
-                              const std::list<octave_lvalue> *lvalue_list);
-
-    octave_lvalue lvalue (void);
+    octave_lvalue lvalue (tree_evaluator *);
 
     void eval_undefined_error (void);
 
@@ -134,7 +125,10 @@
     tree_identifier *dup (symbol_table::scope_id scope,
                           symbol_table::context_id context) const;
 
-    void accept (tree_walker& tw);
+    void accept (tree_walker& tw)
+    {
+      tw.visit_identifier (*this);
+    }
 
     symbol_table::symbol_reference symbol (void) const
     {
@@ -165,7 +159,7 @@
       return new tree_black_hole;
     }
 
-    octave_lvalue lvalue (void)
+    octave_lvalue lvalue (tree_evaluator *)
     {
       return octave_lvalue (); // black hole lvalue
     }