EPPlus/FormulaParsing/LexicalAnalysis/TokenSeparatorProvider.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;

namespace OfficeOpenXml.FormulaParsing.LexicalAnalysis;

public class TokenSeparatorProvider : ITokenSeparatorProvider {
  private static readonly Dictionary<string, Token> _tokens = new();

  static TokenSeparatorProvider() {
    _tokens.Add("+", new("+", TokenType.Operator));
    _tokens.Add("-", new("-", TokenType.Operator));
    _tokens.Add("*", new("*", TokenType.Operator));
    _tokens.Add("/", new("/", TokenType.Operator));
    _tokens.Add("^", new("^", TokenType.Operator));
    _tokens.Add("&", new("&", TokenType.Operator));
    _tokens.Add(">", new(">", TokenType.Operator));
    _tokens.Add("<", new("<", TokenType.Operator));
    _tokens.Add("=", new("=", TokenType.Operator));
    _tokens.Add("<=", new("<=", TokenType.Operator));
    _tokens.Add(">=", new(">=", TokenType.Operator));
    _tokens.Add("<>", new("<>", TokenType.Operator));
    _tokens.Add("(", new("(", TokenType.OpeningParenthesis));
    _tokens.Add(")", new(")", TokenType.ClosingParenthesis));
    _tokens.Add("{", new("{", TokenType.OpeningEnumerable));
    _tokens.Add("}", new("}", TokenType.ClosingEnumerable));
    _tokens.Add("'", new("'", TokenType.String));
    _tokens.Add("\"", new("\"", TokenType.String));
    _tokens.Add(",", new(",", TokenType.Comma));
    _tokens.Add(";", new(";", TokenType.SemiColon));
    _tokens.Add("[", new("[", TokenType.OpeningBracket));
    _tokens.Add("]", new("]", TokenType.ClosingBracket));
    _tokens.Add("%", new("%", TokenType.Percent));
  }

  IDictionary<string, Token> ITokenSeparatorProvider.Tokens => _tokens;

  public bool IsOperator(string item) {
    if (_tokens.TryGetValue(item, out var token)) {
      if (token.TokenType == TokenType.Operator) {
        return true;
      }
    }
    return false;
  }

  public bool IsPossibleLastPartOfMultipleCharOperator(string part) {
    return part == "=" || part == ">";
  }
}