+
−/*
+
−
+
−Copyright (C) 1996-2015 John W. Eaton
+
−
+
−This file is part of Octave.
+
−
+
−Octave is free software; you can redistribute it and/or modify it
+
−under the terms of the GNU General Public License as published by the
+
−Free Software Foundation; either version 3 of the License, or (at your
+
−option) any later version.
+
−
+
−Octave is distributed in the hope that it will be useful, but WITHOUT
+
−ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+
−FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+
−for more details.
+
−
+
−You should have received a copy of the GNU General Public License
+
−along with Octave; see the file COPYING.  If not, see
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−<http://www.gnu.org/licenses/>.
+
−
+
−*/
+
−
+
−#if ! defined (octave_pt_exp_h)
+
−#define octave_pt_exp_h 1
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−
+
−#include <string>
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−#include <list>
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−
+
−class octave_value;
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−class octave_lvalue;
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−
+
−#include "pt.h"
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−#include "symtab.h"
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−
+
−// A base class for expressions.
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−
+
−class
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−tree_expression : public tree
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−{
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−public:
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−
+
−  tree_expression (int l = -1, int c = -1)
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−    : tree (l, c), num_parens (0), postfix_index_type ('\0'),
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−      for_cmd_expr (false), print_flag (false) { }
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−
+
−  virtual ~tree_expression (void) { }
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−
+
−  virtual bool has_magic_end (void) const = 0;
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−
+
−  virtual tree_expression *dup (symbol_table::scope_id,
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−                                symbol_table::context_id context) const = 0;
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−
+
−  virtual bool is_constant (void) const { return false; }
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−
+
−  virtual bool is_matrix (void) const { return false; }
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−
+
−  virtual bool is_cell (void) const { return false; }
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−
+
−  virtual bool is_identifier (void) const { return false; }
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−
+
−  virtual bool is_index_expression (void) const { return false; }
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−
+
−  virtual bool is_assignment_expression (void) const { return false; }
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−
+
−  virtual bool is_prefix_expression (void) const { return false; }
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−
+
−  virtual bool is_unary_expression (void) const { return false; }
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−
+
−  virtual bool is_binary_expression (void) const { return false; }
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−
+
−  virtual bool is_boolean_expression (void) const { return false; }
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−
+
−  virtual bool is_logically_true (const char *);
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−
+
−  virtual bool lvalue_ok (void) const { return false; }
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−
+
−  virtual bool rvalue_ok (void) const { return false; }
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−
+
−  virtual octave_value rvalue1 (int nargout = 1);
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−
+
−  virtual octave_value_list rvalue (int nargout);
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−
+
−  virtual octave_value_list
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−  rvalue (int nargout, const std::list<octave_lvalue> *lvalue_list);
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−
+
−  virtual octave_lvalue lvalue (void);
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−
+
−  int paren_count (void) const { return num_parens; }
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−
+
−  bool is_postfix_indexed (void) const { return (postfix_index_type != '\0'); }
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−
+
−  char postfix_index (void) const { return postfix_index_type; }
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−
+
−  // Check if the result of the expression should be printed.
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−  // Should normally be used in conjunction with
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−  // tree_evaluator::statement_printing_enabled.
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−  bool print_result (void) const { return print_flag; }
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−
+
−  virtual std::string oper (void) const { return "<unknown>"; }
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−
+
−  virtual std::string name (void) const { return "<unknown>"; }
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−
+
−  virtual std::string original_text (void) const;
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−
+
−  virtual void mark_braindead_shortcircuit (void) { }
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−
+
−  void mark_as_for_cmd_expr (void) { for_cmd_expr = true; }
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−
+
−  bool is_for_cmd_expr (void) const { return for_cmd_expr; }
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−
+
−  tree_expression *mark_in_parens (void)
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−  {
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−    num_parens++;
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−    return this;
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−  }
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−
+
−  tree_expression *set_postfix_index (char type)
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−  {
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−    postfix_index_type = type;
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−    return this;
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−  }
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−
+
−  tree_expression *set_print_flag (bool print)
+
−  {
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−    print_flag = print;
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−    return this;
+
−  }
+
−
+
−  virtual void copy_base (const tree_expression& e)
+
−  {
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−    num_parens = e.num_parens;
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−    postfix_index_type = e.postfix_index_type;
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−    print_flag = e.print_flag;
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−  }
+
−
+
−protected:
+
−
+
−  // A count of the number of times this expression appears directly
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−  // inside a set of parentheses.
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−  //
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−  //   (((e1)) + e2)  ==> 2 for expression e1
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−  //                  ==> 1 for expression ((e1)) + e2
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−  //                  ==> 0 for expression e2
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−  int num_parens;
+
−
+
−  // The first index type associated with this expression. This field
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−  // is 0 (character '\0') if the expression has no associated index.
+
−  // See the code in tree_identifier::rvalue for the rationale.
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−  char postfix_index_type;
+
−
+
−  // TRUE if this expression is the EXPR in for loop:
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−  // FOR i = EXPR ... END
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−  bool for_cmd_expr;
+
−
+
−  // Print result of rvalue for this expression?
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−  bool print_flag;
+
−
+
−private:
+
−
+
−  // No copying!
+
−
+
−  tree_expression (const tree_expression&);
+
−
+
−  tree_expression& operator = (const tree_expression&);
+
−};
+
−
+
−#endif