[HarfBuzz] OpenType "mark" Ligatures ... ?

[Richard Wordingham]

On Tue, 23 Apr 2013 15:59:32 -0400
Ed Trager <ed.trager at gmail.com> wrote:
 
> The problem, as illustrated in (1) in the attached image, is that the
> subjoined form of consonant u1A36 TAI THAM LETTER NA or subjoined
> form of consonant u1A3E TAI THAM LETTER MA may commonly be followed
> by a subjoined dependent vowel u1A69 TAI THAM VOWEL SIGN U or u1A6A
> TAI THAM VOWEL SIGN UU and we don't want these to overlap.
> 
> The solution that I thought would work quite well is to create
> ligature glyphs with the correct spacing, as shown in (2) in the
> attached figure. Note that these "ligature" glyphs are "mark" glyphs

Were you planning to deal with the other subscript consonants this
way?  Do the mai sat song lem (MAI SAT, TONE-2) (and mai sat sam lem -
either MAI SAT, MAI SAT, TONE-2 or MAI SAT, TONE-2 TONE-2) ligatures
work?

Richard.