Number::Tolerant::Union(3)

NAME
Number::Tolerant::Union - unions of tolerance ranges

VERSION
version 1.710

SYNOPSIS
 use Number::Tolerant;

 my $range1 = tolerance(10 => to => 12);
 my $range2 = tolerance(14 => to => 16);

 my $union = $range1 | $range2;

 if ($11 == $union) { ... } # this will happen
 if ($12 == $union) { ... } # so will this

 if ($13 == $union) { ... } # nothing will happen here

 if ($14 == $union) { ... } # this will happen
 if ($15 == $union) { ... } # so will this

DESCRIPTION
Number::Tolerant::Union is used by Number::Tolerant to represent the union of multiple tolerances. A subset of the same operators that function on a tolerance will function on a union of tolerances, as listed below.

PERL VERSION
This library should run on perls released even a long time ago. It should work on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the minimum required version will not be increased. The version may be increased for any reason, and there is no promise that patches will be accepted to lower the minimum required perl.

METHODS

  new
  my $union = Number::Tolerant::Union->new(@list_of_tolerances);

There is a "new" method on the Number::Tolerant::Union class, but unions are meant to be created with the "|" operator on a Number::Tolerant tolerance.

The arguments to "new" are a list of numbers or tolerances to be unioned.

Intersecting ranges are not converted into a single range, but this may change in the future. (For example, the union of "5 to 10" and "7 to 12" is not "5 to 12.")

  options
This method will return a list of all the acceptable options for the union.

  Overloading
Tolerance unions overload a few operations, mostly comparisons.

numification
    Unions numify to undef. If there's a better idea, I'd love to hear it.

stringification
    A tolerance stringifies to a short description of itself. This is a set of the union's options, parentheses-enclosed and joined by the word "or"

equality
    A number is equal to a union if it is equal to any of its options.

comparison
    A number is greater than a union if it is greater than all its options.

    A number is less than a union if it is less than all its options.

union intersection
    An intersection ("&") with a union is commutted across all options. In other words:

     (a | b | c) & d  ==yields==> ((a & d) | (b & d) | (c & d))

    Options that have no intersection with the new element are dropped. The intersection of a constant number and a union yields that number, if the number was in the union's ranges and otherwise yields nothing.

TODO
Who knows. Collapsing overlapping options, probably.

AUTHOR
Ricardo Signes <cpan@semiotic.systems>

COPYRIGHT AND LICENSE
This software is copyright (c) 2004 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.