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<p>I've got a situation that I'm not sure how to handle...or even if
Unicode or the rendering engines need update.</p>
<p>In a language using Syriac there is a <i>rish seyame</i> which
can be followed by U+0739 or U+0738</p>
<p><i>rish </i>= 072A</p>
<p><i>seyame </i>= 0308</p>
<p>In TUS, chapter 9, it says:<br>
</p>
<p>
<blockquote type="cite">In Modern Syriac usage, when a word
contains a <i>rish </i>and a <i>seyame</i>, the dot of<br>
the <i>rish </i>and the <i>seyame </i>are replaced by a <i>rish
</i>with two dots above it.</blockquote>
Then, there's a table which indicates this ligature is obligatory:<br>
</p>
<blockquote type="cite">
<p>Table 9-17. Syriac Ligatures</p>
<p>Ligature Classes. As in other scripts, ligatures in Syriac vary
depending on the font style.<br>
Table 9-17 identifies the principal valid ligatures for each
font style. When applicable, these<br>
ligatures are obligatory, unless denoted with an asterisk (*).<br>
</p>
<p>rish seyame Right-joining Right-joining Right-joining BFBS (no
asterisk, so it is obligatory)</p>
</blockquote>
<p><br>
</p>
<p>Finally, in "Developing OpenType Fonts for Syriac Script"
<a class="moz-txt-link-freetext" href="https://docs.microsoft.com/en-us/typography/script-development/syriac">https://docs.microsoft.com/en-us/typography/script-development/syriac</a></p>
<p>In the "Glossary section" it says:</p>
<p>
<blockquote type="cite">
<p><strong>Ligature</strong> - A combination of glyphs that join
to form a single glyph. For example, the 'rish seyame' (U072a
+ U0308) combinations of glyphs are mandatory ligatures for
Syriac. Other ligatures are optional.</p>
</blockquote>
So, it seems clear that 072a+0308 is a mandatory ligature. The
problem I'm seeing is that when this ligature is followed by
U+0739 or U+0738 AND an application does normalization, it changes
the sequence to U+072A U+0739 U+0308 and that breaks the ligature.<br>
</p>
<p>You can see why they are reordering it when you see 0308 is 230
and U+0738 or U+0739 are 220.</p>
0308;COMBINING DIAERESIS;Mn;<b>230</b>;NSM;;;;;N;NON-SPACING
DIAERESIS;;;; <br>
0738;SYRIAC DOTTED ZLAMA HORIZONTAL;Mn;<b>220</b>;NSM;;;;;N;;;;;<br>
0739;SYRIAC DOTTED ZLAMA ANGULAR;Mn;<b>220</b>;NSM;;;;;N;;;;;<br>
<p> </p>
All of the Syriac fonts that I see only handle this sequence <b>U+072A
U+0308 U+0739</b> and not the reordered <b>U+072A U+0739 U+0308</b>
<p>Are the fonts wrong, should they be able to handle U+072A U+0739
U+0308?</p>
<p>Or, is there a special normalization rule for this?</p>
<p>How should <i>rish seyame</i> followed by a below mark like
U+0738 or U+0739 be handled?</p>
<p>Lorna</p>
<p><br>
</p>
<strong></strong>
<p><br>
</p>
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