BytecodeApi.Lexer

Lexical analysis is the first phase that a parser or compiler needs to do in order to break down code into its smallest parts.

First, an enum is needed that represents the type of a token:

public enum FormulaTokenType
{
	OpenParenthesis,
	CloseParenthesis,
	Operator,
	Integer
}

Next, create a Lexer<YourTokenType> with regular expressions for each grammar rule:

Lexer<FormulaTokenType> lexer = Lexer
	.Create<FormulaTokenType>()
	.Ignore(@"[ \t\r\n]+")
	.Match(FormulaTokenType.OpenParenthesis, @"\(")
	.Match(FormulaTokenType.CloseParenthesis, @"\)")
	.Match(FormulaTokenType.Integer, @"[\+-]?[0-9]+")
	.Match(FormulaTokenType.Operator, @"\+|\-|\*|\/");

Finally, to tokenize a string, call the Parse method. The result is a collection of tokens for further processing.

string formula = "(3 + 4) * 15 / ((-10 - 5) * 3)";
TokenCollection<FormulaTokenType> tokens = lexer.Parse(formula);