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List:       perl-datetime
Subject:    Re: DateTime segments in series: Is there prior art?
From:       "Flavio S. Glock" <fglock () gmail ! com>
Date:       2013-08-11 17:25:19
Message-ID: CAHMRfDwEa_S46dAMBV831xJ+25hbXNTfQEtKSDAfHoiqdDKTzQ () mail ! gmail ! com
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http://search.cpan.org/dist/DateTime-Set/lib/DateTime/SpanSet.pm

next() and previous() can be used to determine whether a given point
in time falls between, before, or after the segments.

intersects() can tell whether a new segment would intersect existing segments.

2013/8/11 James E Keenan <jkeen@verizon.net>:
> I need to use DateTime functionality and would like to know
> if the particular functionality I need already exists on
> CPAN.
>
> I need to construct a series of time segments which do not
> overlap but which do not need to be contiguous.  Each
> segment is defined by a start date which is part of the
> segment and by an end date which is the first moment in time
> after the segment's conclusion.
>
> Example:
>
>     2013-01-01 00:00:00
>     2013-02-01 00:00:00
>
>     2013-03-01 00:00:00
>     2013-04-01 00:00:00
>
>     2013-04-01 00:00:00
>     2013-04-15 00:00:00
>
> The above would represent a series of 3 segments consisting,
> in human speak, of January 2013, March 2013 and the first 14
> days of April 2013.  The first two segments are not
> contiguous; the second and third are.
>
> I am permitted to create additional segments before, between
> or after existing segments provided that they do not overlap
> any existing segment.  I can therefore add any of the
> following segments:
>
>     2012-12-15 00:00:00
>     2013-01-01 00:00:00
>
>     2013-02-01 00:00:00
>     2013-03-01 00:00:00
>
>     2013-04-15 00:00:00
>     2013-04-16 00:00:00
>
> ... but I am not permitted to add either of these segments:
>
>     2013-02-15 00:00:00
>     2013-03-15 00:00:00
>
>     2013-04-01 00:00:00
>     2013-04-08 00:00:00
>
> This means that whether initially creating, or subsequently
> updating the series, I must always confirm that a given
> segment does not overlap an existing segment.
>
> Once I have built an object representing a series, I need
> one or more methods to determine whether a given point in
> time:
>
> * falls within a particular segment -- in which case that
> segment is identified;
>
> * falls before the first segment, which is then identified;
>
> * falls between two segments, in which both of those are
> identified; or
>
> * falls after the last segment, which is then identified.
>
> Can you tell me whether prior art exists for this?
>
> Thank you very much.
> Jim Keenan
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