Your comment tells me that you define a day as a half-open interval, and you choose to make midnight part of the "following day"

No, the parallel of what i said for days would be: if one defines a day to be 24 hours that starts at midnight, then midnight would be part of the following day.

The people to which you refer define "day" differently, a period of time that starts at midnight and ends at the next midnight.

I was addressing the OP's question

I know you were trying to answer why it's "open by default" as the OP claimed in his question. The problem is that your answer accepted the premise of a default when there isn't one.

I agree about you about the ease of defining span as [...), but it's not the reason for some non-existing default.

In reply to Re^4: DateTime::Span intersection inconsistencies by ikegami
in thread DateTime::Span intersection inconsistencies by mikeman

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.