/// <summary> returns the lexer that's gonna parse a integer number (valid patterns are: 0, 00, 1, 10),
/// 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 LexInteger()
{
string name = "integer literal";
return(Lex(Scanners.Delimited(Scanners.IsPattern("integer literal", Patterns.IsInteger(), "integer")),
Tokenizers.ForInteger).Rename(name));
}