EpplusFormulaParser/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.Frozen;
using System.Collections.Generic;

namespace EpplusFormulaParser;

internal static class TokenSeparatorProvider {
  private static readonly FrozenDictionary<string, Token> _tokens = new Dictionary<string, Token> {
    { "+", new("+", TokenType.Operator) },
    { "-", new("-", TokenType.Operator) },
    { "*", new("*", TokenType.Operator) },
    { "/", new("/", TokenType.Operator) },
    { "^", new("^", TokenType.Operator) },
    { "&", new("&", TokenType.Operator) },
    { ">", new(">", TokenType.Operator) },
    { "<", new("<", TokenType.Operator) },
    { "=", new("=", TokenType.Operator) },
    { "<=", new("<=", TokenType.Operator) },
    { ">=", new(">=", TokenType.Operator) },
    { "<>", new("<>", TokenType.Operator) },
    { "(", new("(", TokenType.OpeningParenthesis) },
    { ")", new(")", TokenType.ClosingParenthesis) },
    { "{", new("{", TokenType.OpeningEnumerable) },
    { "}", new("}", TokenType.ClosingEnumerable) },
    { "'", new("'", TokenType.String) },
    { "\"", new("\"", TokenType.String) },
    { ",", new(",", TokenType.Comma) },
    { ";", new(";", TokenType.SemiColon) },
    { "[", new("[", TokenType.OpeningBracket) },
    { "]", new("]", TokenType.ClosingBracket) },
    { "%", new("%", TokenType.Percent) },
  }.ToFrozenDictionary();

  public static IDictionary<string, Token> Tokens => _tokens;

  public static bool IsOperator(string item) =>
    _tokens.TryGetValue(item, out var token) && token.TokenType == TokenType.Operator;

  public static bool IsPossibleLastPartOfMultipleCharOperator(string part) => part is "=" or ">";
}