/*
 * Copyright (c) 2003-2008, John Wiegley.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of New Artisans LLC nor the names of its
 *   contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _EXPR_H
#define _EXPR_H

#include "value.h"

namespace ledger {

DECLARE_EXCEPTION(parse_error, std::runtime_error);
DECLARE_EXCEPTION(compile_error, std::runtime_error);
DECLARE_EXCEPTION(calc_error, std::runtime_error);
DECLARE_EXCEPTION(usage_error, std::runtime_error);

class scope_t;
class call_scope_t;

typedef function<value_t (call_scope_t&)> function_t;

class expr_t
{
  struct token_t;

  class parser_t;
  static std::auto_ptr<parser_t> parser;

public:
  class op_t;
  typedef intrusive_ptr<op_t> ptr_op_t;

private:
  ptr_op_t ptr;
  string   str;
  bool     compiled;

  static void initialize();
  static void shutdown();

  friend class session_t;

public:
  expr_t();
  expr_t(const expr_t& other);
  expr_t(const ptr_op_t& _ptr, const string& _str = "");

  expr_t(const string& _str, const unsigned int flags = 0);
  expr_t(std::istream& in, const unsigned int flags = 0);

  virtual ~expr_t() throw();

  expr_t& operator=(const expr_t& _expr);
  expr_t& operator=(const string& _expr) {
    parse(_expr);
    return *this;
  }

  operator bool() const throw() {
    return ptr.get() != NULL;
  }
  string text() const throw() {
    return str;
  }

  // This has special use in the textual parser
  void set_text(const string& txt) {
    str = txt;
  }

  void     parse(const string& _str, const unsigned int flags = 0);
  void     parse(std::istream& in, const unsigned int flags = 0);
	   
  void     compile(scope_t& scope);
  value_t  calc(scope_t& scope);
  value_t  calc(scope_t& scope) const;

  bool	   is_constant() const;
  bool     is_function() const;

  value_t& constant_value();
  const value_t& constant_value() const;

  function_t& get_function();

  void     print(std::ostream& out, scope_t& scope) const;
  void     dump(std::ostream& out) const;
  void     read(const char *& data);
  void     write(std::ostream& out) const;

  static value_t eval(const string& _expr, scope_t& scope);
};

std::ostream& operator<<(std::ostream& out, const expr_t& expr);

} // namespace ledger

#endif // _EXPR_H