[luatex] Lua is removing hyperbolic functions

Hans Hagen pragma at wxs.nl
Wed Jul 9 10:39:07 CEST 2014

On 7/9/2014 8:20 AM, Dirk Laurie wrote:
> Lua is now in 5.3-work3. It contains three things of possible
> importance for LuaTeX:
> 1. Basic UTF-8 (not Unicode) support.

looks ok

> 2. Integer and bitwise arithmetic operators on 64-bit numbers.

A while ago we did some tests with 5.3 ... it looks somewhat slower (was 
beta at that time) but it's anyhow something that needs more testing 
(tex is internally integers so we might have some benefits but number to 
string conversion might need some care at the users end ... not 
something to bother the Lua team with). I don't expect real problems in 
that area.

> 3. cosh, sinh, tanh have been deprecated: not in the manual
>     but still available through a compatibility option that is
>     activated by default.

Normally we activate the compatibility options for a while.

> If any LuaTeX user can give good reasons why the hyperbolic
> functions should stay, now is the time to air them on the
> Lua mailing list (http://lua.org).

If really needed we can always add the more extensive math library (and 
the depricated functions can be written in Lua; in a TeX run one doesn't 
need extreme math performance anyway). The only reason I can think of to 
keep them is that users expect them (any decent calculator has them) and 
keeping them has neglectable overhead.  Getting rid of the power ones 
makes sense.

We have a similar situation in metapost where some common functions need 
to be provided in macros wrapped around built-ins.


PS 1. Changes in hashing and garbage collections are more likely to 
affect Luatex (performance) but we keep an eye on that and tune if needed.

PS 2. Another question is: what will luajit do, as it's already not 5.2 
(fyi: only the faster vm makes sense for luatex, as jitting normally 
slows down a run; we've spent quite some time to get around some issues 
esp with hashing strings that could hit performance hard and make it run 
many times slower than stock Lua).

                                           Hans Hagen | PRAGMA ADE
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