*From*: Igor Zlatkovic <igor stud fh-frankfurt de>*To*: xslt gnome org*Subject*: Re: [xslt] Problem with date:seconds*Date*: Thu, 28 Nov 2002 01:07:58 +0100

Hi, > I think the interpretation in 1.0.20 makes more sense. > > In > http://www.exslt.org/date/functions/seconds/index.html > they use the word "difference" and I think this is > not very exact. > > The difference between 1 and 2 is 1; > the difference between 2 and 1 is also 1 (not -1). No. The difference between 1 and 2 is -1. The difference in mathematical sense is the result of a subtraction and a subtraction is not comutative, means x-y != y-x. The difference in the sense of "distance", which cannot be negative, is what you are looking for. The documentation for date:seconds says: "...the difference between the date/time string and 1970-01-01T00:00:00Z is calculated as with date:difference..." The documentation for date:difference says: "...If the first date occurs before the second date, then the result is a positive duration; if it occurs after the second date, the result is a negative duration." Your date, somewhen anno 2002, is the first date and 1.1.1970 is the second, that is what the first quote says. The second quote says that date:seconds returns a negative value for everything that occurs after 1.1.1970. By doing exactly that, libxslt follows the EXSLT specification. Having said that, I must also say that I believe that the specification for date:difference is wrong. Math says: x - y is 1.) > 0 iff x > y 2.) < 0 iff x < y 3.) = 0 iff x = y If we imagine the time on an axis, any human will percept the growth towards the future. The specification for date:difference agrees to this only in case 3. It assumes that "past > future", which heretises the human logic and perception of time. Ask anyone to compare two data and you'll hear that the former is smaller than the latter. Ciao Igor

**Follow-Ups**:**Re: [xslt] Problem with date:seconds***From:*Bernhard Zwischenbrugger

**References**:**Re: [xslt] Problem with date:seconds***From:*Bernhard Zwischenbrugger

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