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| <H2>Structured Text Overview</H2> |
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| <p>Languages like Arabic and Hebrew are generally written from right to left, |
| but included numbers and phrases in English must be written from left to right. |
| This is the origin of the term "bidirectional" which qualifies these languages.</p> |
| <p>In most computer environments, the text is stored in <em>logical</em> order |
| (the order the text is read) but is reordered into <em>visual</em> order for |
| presentation. For plain text, the Unicode Bidirectional Algorithm |
| (<a href="http://www.unicode.org/reports/tr9/">UBA</a>) |
| generally specifies satisfactorily how to reorder bidirectional text for |
| display. This algorithm, or close to it, is implemented in the presentation |
| systems of a number of platforms, giving them a good handle on bidirectional |
| support.</p> |
| <p>However, all bidirectional text is not necessarily plain text. There are also |
| instances of text structured to follow a given syntax, which should be reflected |
| in the display order. The general algorithm, which has no awareness of these |
| special cases, often gives incorrect results when displaying such structured |
| text.</p> |
| <p>This document describes various examples of this issue, and proposes a |
| methodology to solve the related problems. The types of structured text treated |
| in this document are all excerpted from actual products, including Eclipse.</p> |
| <p>For a general introduction to bidirectional concepts, the reader is kindly |
| referred to the following technical article: "Bidirectional script support: a |
| primer" available at |
| <a href="http://www-128.ibm.com/developerworks/websphere/library/techarticles/bidi/bidigen.html"> |
| http://www-128.ibm.com/developerworks/websphere/library/techarticles/bidi/bidigen.html</a>.</p> |
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| <h3>Working with Structured Text</h3> |
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| <p>Eclipse provides support for correct presentation of structured text. The base |
| functionality can be found in the package <b>"org.eclipse.equinox.bidi"</b>. |
| The methods <code>process()</code> and <code>deprocess()</code> and their variants |
| in class STextProcessor will be a good starting point.</p> |
| |
| <p>Consumers who would like to adjust Bidi environment settings, process bidi |
| text in portions, or directly manage directional formatting will find lower level |
| functionality available in the <b>"org.eclipse.equinox.bidi.advanced"</b> package.</p> |
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| <p>Developers wishing to create handlers for types of structured text not |
| currently supported by Eclipse "out of the box" will create extensions for class STextTypeHandler |
| in package <b>"org.eclipse.equinox.bidi.advanced"</b>. Such new type handlers |
| should register with the <b>"org.eclipse.equinox.bidi.bidiTypes"</b> extension point.</p> |
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