Re: Ligatures (was: Unify the Platforms: Cairo+FreeType+Harfbuzz Everywhere (except TTY))

[Pip Cet]

On Thu, May 21, 2020 at 8:51 PM Clément Pit-Claudel
<address@hidden> wrote:
> On 21/05/2020 15.08, Eli Zaretskii wrote:
> > That would prevent Emacs from controlling what is and what isn't
> > composed, leaving the shaper in charge.  We currently allow Lisp to
> > control that via composition-function-table, which provides a regexp
> > that text around a character must match in order for the matching
> > substring to be passed to the shaper.  We never call the shaper unless
> > composition-function-table tells us to do so.
>
> Does this mean that for each font we need to re-encode the font's logic for 
> deciding whether to use a ligature?

I think

(set-char-table-range composition-function-table t '([".+" 0
font-shape-gstring]))

should work, but it has weird side effects that I'm pretty sure aren't
intended (paren highlighting is broken, for example).

Is that supposed to happen?