The London Perl and Raku Workshop takes place on 26th Oct 2024. If your company depends on Perl, please consider sponsoring and/or attending.


Unicode::EastAsianWidth - East Asian Width properties


    use Unicode::EastAsianWidth;

    $_ = chr(0x2010); # HYPHEN, an ambiguous-width character

    /\p{InEastAsianAmbiguous}/; # True
    /\p{InFullwidth}/;          # False

To mark ambiguous-width characters as InFullwidth:

    BEGIN { $Unicode::EastAsianWidth::EastAsian = 1; }
    use Unicode::EastAsianWidth;

    $_ = chr(0x2010); # HYPHEN, an ambiguous-width character
    /\p{InFullwidth}/;          # True


This module provide user-defined Unicode properties that deal with width status of East Asian characters, as specified in

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:

    BEGIN { $Unicode::EastAsianWidth::EastAsian = 1; }
    use Unicode::EastAsianWidth;

Setting $Unicode::EastAsianWidth::EastAsian at run-time used to work on Perl versions between 5.8 and 5.14 due to an implementation detail, but it will no longer work on Perl 5.16 and later versions, and hence is not recommended.




Audrey Tang <>


This work is under the CC0 1.0 Universal license.

To the extent possible under law, 唐鳳 has waived all copyright and related or neighboring rights to Unicode-EastAsianWidth.

This work is published from Taiwan.