Julian Date Question in ASOC

Scripting Forums AppleScriptObjC and Xcode
#1

Dear Friends,

I have been banging my head for hours on this issue, I guess I am too tired to find a solution:

I have this Applescript date: “Tuesday, October 7, 1997 12:00:00 AM”. (reference date)

I need to get a Julian date from this reference date to the date of “21/04/2012” (April 21st)

The result should be shown in integer : 5310 (days)

I had this line that worked for many years:


 set calculated_julian_date to ((the_date - (reference_date)) / days) div 1

But I can’t do this, because if I simply:


date(the_date)

I get this weird result:

<geraLinhaDigitalClass @0x400d0bc00: OSAID(15)>

Thank you for any help…

#2

Have a look in my book at the gotchas chapter – that explains the problem with using date as a specifier, as well as the workarounds.

#3

Thanks Shane,

if i use this line:


 set the_date to current application's date "Tuesday, October 7, 1997 12:00:00 AM" as date

It results in:

<NSAppleEventDescriptor: 'ldt '($002C5FB000000000$)>

And when I try to do the maths, it results in this error:

Can’t make «script» into type number or date. (error -1700)

I guess I have to go to a 100% objc solution…

#4

I am able to set the reference date using this code:



set reference_date to current application's NSDate's |date|()
        set theCal to current application's NSCalendar's currentCalendar()
        set theComponents to theCal's components_fromDate_(current application's NSMonthCalendarUnit,reference_date)
  
        set theComponents's |month| to 10
        set theComponents's |Day| to 7
        set theComponents's |Year| to 1997
        set theComponents's |Minute| to 0
        set theComponents's |Hour| to 0
        set theComponents's |Second| to 0

set newDate to theCal's dateFromComponents_(theComponents)

I think to retrieve the count of days in between the reference_date and the_date I need to use the equivalent in ASOC to this method:


- (NSTimeInterval)timeIntervalSinceDate:(NSDate *)anotherDate

Can someone help me write the line above in ASOC?

Thanks!

#5

I wrote this and it works:



-(NSString *)returnJulianCount:(NSString *)theInputDate theReferenceDate:(NSString *) theReferencedate{
    
    NSDateFormatter *dateFormat1 = [[NSDateFormatter alloc] init];
    [dateFormat1 setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    NSDate *dateEvent1 = [dateFormat1 dateFromString:theInputDate];
	
    NSDateFormatter *dateFormat2 = [[NSDateFormatter alloc] init];
    [dateFormat2 setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    NSDate *dateEvent2 = [dateFormat2 dateFromString:theReferencedate];
	
    NSTimeInterval timeDifference = [dateEvent1 timeIntervalSinceDate:dateEvent2];
    NSLog(@"timeDifference = %.0f",timeDifference);
    
    double minutes = timeDifference / 60;
    double hours = minutes / 60;
    double seconds = timeDifference;
    double days = minutes / 1440;
    
    NSString *dayCount = [NSString stringWithFormat:@"%f",days];
    [dateFormat1 release];
    [dateFormat2 release];

	
    return dayCount ;
}

Just call it from my AS like this:



set dataJuliana to GetJulianDateClass's returnJulianCount_theReferenceDate_("2012-04-21 03:00:00","1997-10-07 03:00:00")

I hope it helps someone…

Thanks!

#6

Bernardo, your method is just a date subtraction regardless of the calendar type.
What is the characteristic of the julian calendar?

By the way, this is a shorter version, which returns the number of days as an integer


- (NSString *)returnJulianCount:(NSString *)theInputDate theReferenceDate:(NSString *) theReferencedate{
    
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    NSDate *inputDate = [dateFormatter dateFromString:theInputDate];
    NSDate *referenceDate = [dateFormatter dateFromString:theReferencedate];
    [dateFormatter release];
    
    return [NSString stringWithFormat:@"%.0f", [inputDate timeIntervalSinceDate:referenceDate] / 86400];
}
#7

Well that is almost an AppleScript date – it just needs coercing to one. Make you need parentheses:

 set the_date to (current application's date "Tuesday, October 7, 1997 12:00:00 AM") as date
#8

Dear Shane and StefanK,

Thank you for being so kind.