188   int pre_pos = in_->position();  in Scan()
189   if (in_->IsEnd()) return DateToken::EndOfInput();  in Scan()
190   if (in_->IsAsciiDigit()) {  in Scan()
191     int n = in_->ReadUnsignedNumeral();  in Scan()
192     int length = in_->position() - pre_pos;  in Scan()
195   if (in_->Skip(':')) return DateToken::Symbol(':');  in Scan()
196   if (in_->Skip('-')) return DateToken::Symbol('-');  in Scan()
197   if (in_->Skip('+')) return DateToken::Symbol('+');  in Scan()
198   if (in_->Skip('.')) return DateToken::Symbol('.');  in Scan()
199   if (in_->Skip(')')) return DateToken::Symbol(')');  in Scan()
200   if (in_->IsAsciiAlphaOrAbove()) {  in Scan()
203     int length = in_->ReadWord(buffer, 3);  in Scan()
209   if (in_->SkipWhiteSpace()) {  in Scan()
210     return DateToken::WhiteSpace(in_->position() - pre_pos);  in Scan()
212   if (in_->SkipParentheses()) {  in Scan()
215   in_->Next();  in Scan()