NAME

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

VERSION

version 1.42

 $Id: /my/cs/projects/tolerant/trunk/lib/Number/Tolerant/Union.pm 22014 2006-05-11T23:00:09.416140Z rjbs  $

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 the Number::Tolerant manpage 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.

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, <rjbs@cpan.org>

COPYRIGHT

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