AppsheetEpplus/FormulaParsing/LexicalAnalysis/TokenizerContext.cs

/*******************************************************************************
 * You may amend and distribute as you like, but don't remove this header!
 *
 * EPPlus provides server-side generation of Excel 2007/2010 spreadsheets.
 * See http://www.codeplex.com/EPPlus for details.
 *
 * Copyright (C) 2011  Jan Källman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.

 * This library 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 Lesser General Public License for more details.
 *
 * The GNU Lesser General Public License can be viewed at http://www.opensource.org/licenses/lgpl-license.php
 * If you unfamiliar with this license or have questions about it, here is an http://www.gnu.org/licenses/gpl-faq.html
 *
 * All code and executables are provided "as is" with no warranty either express or implied.
 * The author accepts no liability for any damage or loss of business that this product may cause.
 *
 * Code change notes:
 *
 * Author							Change						Date
 * ******************************************************************************
 * Mats Alm   		                Added       		        2013-03-01 (Prior file history on https://github.com/swmal/ExcelFormulaParser)
 *******************************************************************************/

using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace AppsheetEpplus;

public class TokenizerContext {
  public TokenizerContext(string formula) {
    if (!string.IsNullOrEmpty(formula)) {
      _chars = formula.ToArray();
    }
  }

  private readonly char[] _chars;
  private readonly List<Token> _result = new();
  private StringBuilder _currentToken = new();

  public char[] FormulaChars => _chars;

  public IList<Token> Result => _result;

  public bool IsInString { get; private set; }

  public void ToggleIsInString() {
    IsInString = !IsInString;
  }

  internal int BracketCount { get; set; }

  public string CurrentToken => _currentToken.ToString();

  public bool CurrentTokenHasValue =>
    !string.IsNullOrEmpty(IsInString ? CurrentToken : CurrentToken.Trim());

  public void NewToken() {
    _currentToken = new();
  }

  public void AddToken(Token token) {
    _result.Add(token);
  }

  public void AppendToCurrentToken(char c) {
    _currentToken.Append(c.ToString());
  }

  public void AppendToLastToken(string stringToAppend) {
    _result.Last().Append(stringToAppend);
  }

  public void SetLastTokenType(TokenType type) {
    _result.Last().TokenType = type;
  }

  public void ReplaceLastToken(Token newToken) {
    var count = _result.Count;
    if (count > 0) {
      _result.RemoveAt(count - 1);
    }
    _result.Add(newToken);
  }

  public Token LastToken => _result.Count > 0 ? _result.Last() : null;
}