parser/tree/selection_node.hpp

0001 // selection_node.hpp
0002 // Copyright (c) 2007-2009 Ben Hanson (http://www.benhanson.net/)
0003 //
0004 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0005 // file licence_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 #ifndef BOOST_SPIRIT_SUPPORT_DETAIL_LEXER_PARSER_TREE_SELECTION_NODE_HPP
0007 #define BOOST_SPIRIT_SUPPORT_DETAIL_LEXER_PARSER_TREE_SELECTION_NODE_HPP
0008
0009 #include "node.hpp"
0010
0011 namespace boost
0012 {
0013 namespace lexer
0014 {
0015 namespace detail
0016 {
0017 class selection_node : public node
0018 {
0019 public:
0020     selection_node (node *left_, node *right_) :
0021         node (left_->nullable () || right_->nullable ()),
0022         _left (left_),
0023         _right (right_)
0024     {
0025         _left->append_firstpos (_firstpos);
0026         _right->append_firstpos (_firstpos);
0027         _left->append_lastpos (_lastpos);
0028         _right->append_lastpos (_lastpos);
0029     }
0030
0031     virtual ~selection_node ()
0032     {
0033     }
0034
0035     virtual type what_type () const
0036     {
0037         return SELECTION;
0038     }
0039
0040     virtual bool traverse (const_node_stack &node_stack_,
0041         bool_stack &perform_op_stack_) const
0042     {
0043         perform_op_stack_.push (true);
0044
0045         switch (_right->what_type ())
0046         {
0047         case SEQUENCE:
0048         case SELECTION:
0049         case ITERATION:
0050             perform_op_stack_.push (false);
0051             break;
0052         default:
0053             break;
0054         }
0055
0056         node_stack_.push (_right);
0057         node_stack_.push (_left);
0058         return true;
0059     }
0060
0061 private:
0062     // Not owner of these pointers...
0063     node *_left;
0064     node *_right;
0065
0066     virtual void copy_node (node_ptr_vector &node_ptr_vector_,
0067         node_stack &new_node_stack_, bool_stack &perform_op_stack_,
0068         bool &down_) const
0069     {
0070         if (perform_op_stack_.top ())
0071         {
0072             node *rhs_ = new_node_stack_.top ();
0073
0074             new_node_stack_.pop ();
0075
0076             node *lhs_ = new_node_stack_.top ();
0077
0078             node_ptr_vector_->push_back (static_cast<selection_node *>(0));
0079             node_ptr_vector_->back () = new selection_node (lhs_, rhs_);
0080             new_node_stack_.top () = node_ptr_vector_->back ();
0081         }
0082         else
0083         {
0084             down_ = true;
0085         }
0086
0087         perform_op_stack_.pop ();
0088     }
0089 };
0090 }
0091 }
0092 }
0093
0094 #endif