/// <summary> returns the lexer that's gonna parse a decimal integer number (valid patterns are: 1, 10, 123),
/// and convert the string to a Long token.
/// The difference between integer() and decInteger() is that decInteger does not allow a number starting with 0.
/// </summary>
/// <returns> the lexer.
/// </returns>
public static Lexer LexDecimalLong()
{
string name = "decimal integer literal";
return(Lex(Scanners.Delimited(Scanners.IsPattern(name, Patterns.IsDecInteger(), "decInteger")),
Tokenizers.ForLong));
}