parse method
Implementation
@override
CronSchedule parse(String cron) {
final fields = _presets(cron).toLowerCase().trim().split(' ');
assert(
fields.length == 5,
'The cron format must be have five time and date fields separated by at '
'least one blank',
);
final minutes = _parseField(fields[0], 0, 59);
final hours = _parseField(fields[1], 0, 23);
final dom = _parseField(fields[2], 1, 31);
final months = _parseField(_normalize(fields[3], _months), 1, 12);
final dow = _mapToDartWeekday(
_parseField(_normalize(fields[4], _weekdays), 0, 7),
);
return CronSchedule(
minutes: minutes,
hours: hours,
daysOfMonth: dom,
months: months,
daysOfWeek: dow,
);
}