/*
 * Copyright (c) 2003-2025, 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.
 */

/**
 * @defgroup expr Value expressions
 */

/**
 * @file   token.h
 * @author John Wiegley
 *
 * @ingroup expr
 */
#pragma once

#include "expr.h"

namespace ledger {

struct expr_t::token_t : public noncopyable
{
  enum kind_t {
    ERROR,                      // an error occurred while tokenizing
    VALUE,                      // any kind of literal value
    IDENT,                      // [A-Za-z_]+
    MASK,                       // /regexp/

    LPAREN,                     // (
    RPAREN,                     // )
    LBRACE,                     // {
    RBRACE,                     // }

    EQUAL,                      // ==
    NEQUAL,                     // !=
    LESS,                       // <
    LESSEQ,                     // <=
    GREATER,                    // >
    GREATEREQ,                  // >=

    ASSIGN,                     // =
    MATCH,                      // =~
    NMATCH,                     // !~
    MINUS,                      // -
    PLUS,                       // +
    STAR,                       // *
    SLASH,                      // /
    ARROW,                      // ->
    KW_DIV,                     // div

    EXCLAM,                     // !, not
    KW_AND,                     // &, &&, and
    KW_OR,                      // |, ||, or
    KW_MOD,                     // %

    KW_IF,                      // if
    KW_ELSE,                    // else

    QUERY,                      // ?
    COLON,                      // :

    DOT,                        // .
    COMMA,                      // ,
    SEMI,                       // ;

    TOK_EOF,
    UNKNOWN

  } kind;

  char        symbol[6];
  value_t     value;
  std::size_t length;

  explicit token_t() : kind(UNKNOWN), length(0) {
    TRACE_CTOR(expr_t::token_t, "");
  }
  ~token_t() throw() {
    TRACE_DTOR(expr_t::token_t);
  }

  token_t& operator=(const token_t& other) {
    if (&other == this)
      return *this;
    assert(false);              // only one token object is used at a time
    return *this;
  }

  void clear() {
    kind      = UNKNOWN;
    length    = 0;
    value     = NULL_VALUE;
    symbol[0] = '\0';
  }

  int  parse_reserved_word(std::istream& in);
  void parse_ident(std::istream& in);
  void next(std::istream& in, const parse_flags_t& flags);
  void rewind(std::istream& in);
  void unexpected(const char wanted = '\0');
  void expected(const char wanted, const int c);
  void expected(const kind_t wanted);
};

std::ostream& operator<<(std::ostream& out, const expr_t::token_t::kind_t& kind);
std::ostream& operator<<(std::ostream& out, const expr_t::token_t& token);

} // namespace ledger
