From: "Peter Kirk" <[EMAIL PROTECTED]> > >Of course this is not a standard normalization form, but using this pseudo > >combining class may help render the last two coded strings (in my quote > >above) equivalently in renderers. > >This works even in the case where there are multiple diacritics (noted CC1 > >and CC2 below): > > <NBSP,CC1,CC2> > >is then treated as if it was: > > <WJ,SP,WJ,CC1,CC2> > >and then the pseudo-normalization had given: > > <WJ,SP,CC1,CC2,WJ> > >or: > > <WJ,SP,CC2,CC1,WJ> > >(depending on the canonical reordering of CC1 and CC2, i.e. of their > >relative combining class) > > This trick doesn't work if any of the CC's are in combining class zero.
Of course, but which combining character of combining class 0 does need to combine with NBSP in a way that affect renderers? Do you think about sequences like <NBSP,CGJ>? Or about issues when rendering <07A6;THAANA ABAFILI;Mn;0;NSM;;;;;N;;;;;> after <NBSP> which of wourse would be handled only as <WJ,SP,WJ,THAANA ABAFILI> ? Or about: <0901;DEVANAGARI SIGN CANDRABINDU;Mn;0;NSM;;;;;N;;;;;> after <NBSP> rendered as if it was <WJ,SP,WJ,CANDRABINDU> ? Or about <0903;DEVANAGARI SIGN VISARGA;Mc;0;L;;;;;N;;;;;> after <NBSP> which is this time a "Mc" character ? Or about all the Indic vowels which do not seem to be really combining on NBSP but would be rendered as a space followed by a defective isolated form of the vowel (so without vowel glyphs reordering around the space) ? Just curious... If we just say that <NBSP> behaves in all cases in renderers as if it was <WJ,SP,WJ> where WJ is reordered with a pseudo-combining class 256, it solves much problems with the interpretation of NBSP, and it looks like if NBSP was a space letter; however NBSP is not a "Lo" character but really a "Zs" whitespace and thus justifiable out of the end margin; also NBSP does not prohibit word break but only line breaks), so it is more like if it was in fact: <LJ,SP,LJ> where LJ is a line-joiner, distinct also from ZWJ (zero-width joiner) used to hint ligatures but which does not brohibit any break.
