Number::Tolerant::Union(3) unions of tolerance ranges


version 1.708


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


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.



  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.'')


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


Tolerance unions overload a few operations, mostly comparisons.
Unions numify to undef. If there's a better idea, I'd love to hear it.
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''
A number is equal to a union if it is equal to any of its options.
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.


Who knows. Collapsing overlapping options, probably.


Ricardo Signes <[email protected]>


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.