---- On Tue, 25 Sep 2018 23:26:10 +0200 Hans Hagen <j.ha...@xs4all.nl> wrote
----
> On 9/25/2018 9:33 PM, Marcel Krüger wrote:
> > Hi,
> >
> > while looking into a [luaotfload bug][bug] caused by the fontloader
> > being confused when LuaTeX overwrites the `parameters` in a
> > cached font table, I wondered why `write_lua_parameters` always
> > creates a new table instead of altering a potentially preexisting table.
> >
> > Changing this should lead to some small performance improvement
> > because Lua no longer has to create a new table every time a cached
> > font table is queried and more importantly it allows additional string
> > keys in `parameters` to be preserved.
>
> sounds more like an issue of luaotfload ... it should manage the
> parameters well
I do not think luaotfload is responsible especially because Ulrike Fischer
got a similar problem on ConTeXt with
\starttext
foo
\ctxlua{for ii,vv in font.each() do end }
bar
\stoptext
She proposed that the ConTeXt fontloader might benefit from overloading
`font.each()` similar to `font.getfont` if the engine should not be changed.
In some personal experiments
local function fonteach_next(max, f)
repeat
f = f + 1
if f > max then return end
until font.frozen(f) ~= nil
return f, font.getfont(f) or font.fonts[f]
end
font.each = function() return fonteach_next, font.max(), 0 end
seemed to fix the problem.
>
> we're not going to change the current behaviour in the engine which is
> creating these tables (same for math constant etc) from mem (changing
> such things might solve your specific issue but introduce issues for
> others)
While I agree that keeping compatibility is important I do not really understand
how this would lead to issues.
Especially the parameters known to LuaTeX are still updated, so the only change
I can see here would be if someone relies on LuaTeX dropping some table
values...
Is there a problem I missed?
Best regards
Marcel
>
> -----------------------------------------------------------------
> Hans Hagen | PRAGMA ADE
> Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
> tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
> -----------------------------------------------------------------
>
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