Motion P1788/M0021.2:IntervalOverlapping NO

[Alan Eliasen <eliasen@xxxxxxxxxxxxxx>]

   I vote NO on M0021.2.

   I do not believe that the set of operations listed in this paper are
generally useful, and it enlarges the specification without clear
benefit.  There is nothing in the paper that could not be obtained by
allowing access to the infimum and supremum of each interval and
allowing the user to make their own comparisons.

   In addition, I think some of the comparisons are actively dangerous,
such as "meets" or "starts" or "finishes" or "finishedBy" or "startedBy"
or "metBy", or "equalP".  These essentially require testing equality of
two imprecise floating-point numbers, and doing something based on that
test.  This is almost always bad practice, and usually indicates
misunderstanding of uncertainties in floating-point math.  In an
ordinary numeric program, if you're doing something like

   if a==1.1
      doSomething()

  Then your program should probably be considered untrustable and will
likely not do what you intend.  This proposal essentially
institutionalizes that untrustable, worst-practice behavior.

  When comparing intervals, where endpoints are rounded outward, these
operations will probably never do what you want, as "very close"
endpoints will not actually be coincident.

-- 
  Alan Eliasen
  eliasen@xxxxxxxxxxxxxx
  http://futureboy.us/