There is a requirement in some cases, depending on the typographical convention in use, to form a ligature between the combining marks U+05BD HEBREW POINT METEG and any one of the three "hataf" vowel points U+05B1, U+05B2 and U+05B3. But there are also some exceptions i.e. cases in which the ligature should not be formed when the default is for it to be formed, and possibly cases when it should be formed when by default it is not to be formed.
The Unicode standard, 4.0 section 15.2, specifies ZWJ and ZWNJ as the characters to use for promoting or inhibiting ligatures. But the text seems to assume that the characters being ligated are base characters. A problem arises when ZWJ or ZWNJ is inserted between combining marks to promote or inhibit ligation: as non-combining control characters these characters break the combining sequence, such that the following combining mark forms a defective combining sequence whose rendering is undefined.
An alternative that has been suggested has been to use CGJ between the combining marks. This has the advantage that CGJ is itself a combining mark and so does not break the combining sequence; but the disadvantage that this is one character, not two, and so cannot be used separately to promote or inhibit ligation. The more serious problem is that this use does not accord with the defined use of CGJ which is explicitly not to affect ligation.
Can anyone on this list advise what should be done in this case?
-- Peter Kirk [EMAIL PROTECTED] (personal) [EMAIL PROTECTED] (work) http://www.qaya.org/
