number method
void
number()
Implementation
void number() {
while (peek() != null && isDigit(peek()!)) {
advance();
}
if (peek() == '.' && (peekNext() != null && isDigit(peekNext()!))) {
advance();
while (peek() != null && isDigit(peek()!)) {
advance();
}
addToken(
TokenType.double, double.parse(source.substring(start, current)));
} else {
addToken(TokenType.integer, int.parse(source.substring(start, current)));
}
}