string-direction

string-direction is a ruby String extension for automatic detection of the direction (left-to-right, right-to-left or bi-directional) in which a text should be displayed.

Mainly, it exposes four new methods to String instances. direction can return ltr, rtl or bidi depending on the characters used in the string. There are as well is_ltr?, is_rtl? and is_bidi? convenient predicate methods.

#encoding: utf-8
require 'string-direction'

p 'english'.direction #=> "ltr"
p 'العربية'.direction #=> "rtl"
p 'english العربية'.direction #=> "bidi"

p 'english'.is_ltr? #=> "true"
p 'العربية'.is_ltr? #=> "false"
p 'العربية'.is_rtl? #=> "true"
p 'english العربية'.is_bidi? #=> "true"

Unicode marks

If Unicode marks left-to-right (\u200e) or right-to-left (\u200f) are present, then string-direction rely on them instead of trying to guess from the characters used.

p "\u200eالعربية".direction #=> "ltr"
p "\u200fEnglish".direction #=> "rtl"

Changing default right-to-left scripts

By default, string-direction consider following scripts to have a right-to-left writing:

• Arabic
• Hebrew
• Nko
• Kharoshthi
• Phoenician
• Syriac
• Thaana
• Tifinagh

You can change easily these defaults interacting with the array StringDirection.rtl_scripts

p 'ᚪᚫᚬᚭᚮᚯ'.direction #=> "ltr"
StringDirection.rtl_scripts << 'Runic'
p 'ᚪᚫᚬᚭᚮᚯ'.direction #=> "rtl"

This can be useful, mainly, for scripts that have both left-to-right and right-to-left representations:

• Bopomofo
• Carian
• Cypriot
• Lydian
• Old_Italic
• Runic
• Ugaritic

Keep in mind than only scripts recognized by Ruby regular expressions are allowed.

Release Policy

string-direction follows the principles of semantic versioning.

Disclaimer

I'm not an expert neither in World scripts nor in Unicode. So, please, if you know some case where this library is not working as it should be, open an issue and help improve it.

Thanks

Omniglot.com, where I learnt which Ruby recognized scripts have a right-to-left writing system.

LICENSE

Copyright 2013 Marc Busqué - marc@lamarciana.com

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.