Unicode::EastAsianWidth provide user-defined Unicode properties that deal with
width status of East Asian characters, as specified in
http://www.unicode.org/unicode/reports/tr11/.

It exports the following functions to the caller's scope, to be used by Perl's
Unicode matching system: InEastAsianFullwidth, InEastAsianHalfwidth,
InEastAsianAmbiguous, InEastAsianNarrow InEastAsianWide, InEastAsianNeutral.

In accord to TR11 cited above, two additional context-sensitive properties are
exported: InFullwidth (union of Fullwidth and Wide) and InHalfwidth (union of
Halfwidth, Narrow and Neutral).

Ambiguous characters are treated by default as part of InHalfwidth, but you can
modify this behaviour by assigning a true value to
$Unicode::EastAsianWidth::EastAsian at compile time within a BEGIN block before
loading this module