Fyrimynd:ISO 15924 direction/doc

Usage

The template returns, for an ISO script code, the direction rtl, ltr, ttb, inh, mixed, or <blank>.

• {{ISO 15924 direction|Hebr}} → rtl
• {{ISO 15924 direction|Latn}} → ltr

Options

The output texts rtl, ltr, ttb, mixed, inh, or <blank>:

• {{ISO 15924 direction|Hebr|ltr=left-to-right|rtl=right-to-left}} → right-to-left

• {{ISO 15924 direction|Mong|ttb=top-to-bottom}} → top-to-bottom

• {{ISO 15924 direction|Zyyy|ltr=left-to-right|rtl=right-to-left|mixed=both directions|default=unknown}} → both directions

Output <blank> (meaning: unknown) can be set to show any text:

• {{ISO 15924 direction|Mang|default=unknown}} → unknown

How is it determined

The direction is determined as follows.

• First, if a script is present in Unicode, Unicode Bidi-direction is derived for that Unicode script.

There are 94 scripts in Unicode (those ISO codes that have an alias). All regular scripts have a single "Strong" in Unicode direction. That is, all characters in a Unicode script that are "Strong", have the same directionality: either right-to-left (rtl) or left-to-right (ltr). Within a script there are no opposing directions present. There can be characters with "Weak" or "Neutral" direction (i.e., direction through context), but these do not alter other characters diretionality. One exception: script "Zyyy" conatains characters with either direction. Therefor, Zyyy has direction "mixed".

• Second, all other scripts, that are not defined in Unicode, can have their direction set manually in this template.

How to add a script direction

The Unicode scripts are determined as of version 6.0, and should be complete & correct. That (upper) part of the list should not be changed unless for errors. An script directionality can be added:

 | <!--
end of Unicode-determined -->
 | Abcd
 | Defg = {{{ltr|ltr}}
 | Pqrs
 | Tuvw = {{{rtl|rtl}}
 | #default={{{default|}}}

The parameters as shown keep the output text option available.

Background

For scripts in Unicode, the direction is determined as follows. Each character in a script (say Hebr) has a single property bidi-type. The value of that bidi-type is from a list, and its usage is described in the Unicode Bidi Algorithm (UAX#9).

The bidi-type can determine the direction, which can be a Strong, Neutral or Weak one. Strong directions are independent, like for the Latin alphabet A-Z. Neutral and Weak directions are dependent on context (think nearby other characters), and are used e.g. with decimals, diacritics and punctuation marks.

Within the character set of a script (e.g. Hebr=Hebrew script has 133 characters in Unicode), there are Strong characters, all are right-to-left. Other characters are Neutral, and so have not direction by their own. This is true for all (but one) scripts in Unicode: within a script, all Strong directions are the same.

From there this templates is build: All scripts in Unicode (but one exception, see below) have a single Strong direction. That direction is used here in this template. The exception is: Zyyy, Common, which is a collection of various characters that can be of either direction.

General information on ISO 15924 templates

Maintenance

Overview of ISO 15924 templates

Item	Publisher	Details	Example	Definition in template	Usage in page	Notes
Code	ISO 15924	Alpha-4	Arab	{{ISO 15924 code}}	{{ISO 15924/footer}}, /doc
Number	ISO 15924	Range 000–999	234	{{ISO 15924 number}}
Name	ISO 15924	Descriptive name		{{ISO 15924 name}}		ISO name can differ from Unicode (alias) name
Alias1	ISO 159242	Script name as used in Unicode	Arabic	{{ISO 15924 alias}}
Script direction	Unicode	Can vary per character, but all Unicode scripts (so far) have a single main direction	rtl	{{ISO 15924 direction}}
WP-name	en:Wikipedia	WP content page name for the script	Arabic script	{{ISO 15924/wp-name}}
WP-category	en:Wikipedia	WP category name for the script	Arabic script	{{ISO 15924/wp-category}}		Category:Arabic script
Script example character	en:Wikipedia	Example character in userboxes	ع	{{ISO 15924/script-example-character}}	User boxes	e.g. Category:User Arab
Overview & relation ISO – Unicode	en:Wikipedia			{{ISO 15924 script codes and Unicode}}
Redirect	en:Wikipedia	Redirect template		{{R from ISO 15924 code}}	Redirects
Overview	en:Wikipedia	Overview for templates check		{{ISO 15924/overview}}
Subpages	en:Wikipedia	list		Special:PrefixIndex/Template:ISO_15924
1 Property Value Alias. 2 The alias name is decided by the Unicode Consortium, and is also included in the ISO 15924 data tables.

ISO updates

The ISO 15924 list of script codes is updated regularly, usually at least once a year. The current list is complete per 15 november 2014 (2014 -11-15), and defines 175 codes (code, number, script name).

Note: when resolving red links or wrong links, edit {{ISO 15924/wp-name}} or {{ISO 15924/wp-category}}. That is where the connection between ISO code and Wikipedia names is made.

Sources

• ISO 15924
• ISO values