Right-to-left languages such as Arabic, Persian and Hebrew require the right CSS properties. If the entire wiki is right-to-left, you probably only need to set this property for the body element. If you mix left-to-right and right-to-left, however, you need more fine-grained control.

Thus:

No: Neither CSS nor text formatting rules support it, and neither can be changed.

Optional: The CSS can be modified such that the body element can be designated right-to-left. Maybe text formatting rules exist that can added to designate different sections as right-to-left (usually inserting an appropriately styled DIV element).

Plugin: Provide such formatting rules or CSS changes via a plugin.

Yes: Both CSS and text formatting rules support it by default.

Right-to-left support is NOT CSS support. Direction should be specied in the HTML, not in the CSS - it is part of the content, not the presentation. Good support require specifing of element langauge and direction in the html. CSS may be used to control the presentation of those elements.

Because direction is implied by the language used, supporting language also automatically support direction. Language support is important for screenreaders, and may be used to filter search results.

Levels of Right-to-left support:

1. Wiki - all pages in the wiki are using save language and direction.
2. Page - each page may have different langauge and direction, e.g. English page in Hebrew wiki.
3. Section - each page section may have different language and direction. e.g. an English blockquote inside an Hebrew page.
4. Inline - a way to mark few words with different langauge and direction. e.g. short English quote inside Hebrew paragraph.

Here are examples from MoinMoin:

• Wiki - default_lang = language-name - configuration option.
• Page - #language language-name - set in each page header. If not set, defaults to default_lang
• Section - [[language-name]] macro - switch language and direction
• Inline - [[langauge-name(text...)]] macro - enclose text in <span lang=language-name dir=language-direction></span>

Related issues:

• Theme language and direction - switch theme language and direction per user
• Page names - support page names in any language
• User names - suppot user names in any langauge
• Password - support password in any language (not all browsers support that)