On Thu, 17 Aug 2017 18:34:56 +0530 Shriramana Sharma via Unicode <[email protected]> wrote:
> Thanks for your reply, but how can characters be used portably if they > are not part of the published standard yet? Or is it that hereafter > both Unicode Standard + Unicode Emoji Standard will be parallelly > portable or something like that? A hypothetical application could correctly claim to correctly render every sequence (up to some reasonable length limit) of assigned Unicode characters from a recent version (e.g. 10.0) while completely ignoring the Unicode Emoji Standard. That doesn't mean a great deal though, as Unicode appears not to be a standard for the encoding of text strings, but merely for the encoding of characters. Thus, at the level of undisputable text, in Indic scripts there appears to be no provision for the ordering of multiple left matras that are to be stored in logical order (i.e. backing order) after the onset consonants. (Thus, this is not a problem for the Thai script.) Fortunately, there is no good evidence that the occurrence of multiple distinct left matras is anything but a typing error, though I can easily see how it might be used as a lexicographical convention on the fuzzy edge of plain text. In a similar vein, in Malayalam, we get repeats of the 2-part vowel U+0D4B MALAYALAM VOWEL SIGN OO (see Cibu Johny's report at https://lists.freedesktop.org/archives/harfbuzz/2013-February/002945.html), but I'm not sure what the legitimate encodings of the example word കോോോ (typed here as <U+0D15, U+0D4B, U+0D4B, U+0D4B>) are. Richard.

