Draft 1 of UAX#29 'Unicode Text Segmentation' for Unicode 11.0.0 implies that it might be considered desirable to have a word boundary in 'aquaφοβία' or a grapheme cluster break in a coding such as <006C, U+0901 DEVANAGARI SIGN CANDRABINDU> for el candrabindu (l̐), which should be <006C, U+0310 COMBINING CANDRABINDU> in accordance with the principle of script separation. Why are such breaks desirable?
I can understand an argument that these should be tolerated, as an application could have been designed on the basis that script boundaries imply word boundaries (not true for Japanese) and that word boundaries imply grapheme cluster boundaries (not true for Sanskrit, where they don't even imply character boundaries.) There are some who claim that the Laotian consonant place holder is the letter 'x' rather than the multiplication sign, U+00D7, which does have Indic_syllabic_category=Consonant_Placeholder. (I trust no-one is suggesting that there should be grapheme cluster boundary between U+00D7 with script=common and a non-spacing Lao vowel any more than there would be with a Lao consonant.) Richard.
