On Wed, May 8, 2013 at 2:49 AM, Kip Warner <kip@thevertigo.com> wrote:

Hey Luigi,

I find the \texenginename and \texengineversion useful for retrieving
the backend name and version. They work fine when using the vanilla
LuaTeX backend. However, when using LuaJitTeX, the aforementioned
macros still seem to retrieve LuaTeX specific information and not
LuaJitTeX - unless I'm doing something wrong. I was careful to ensure I
passed --engine=luajittex to context as well.

--
Kip Warner -- Software Engineer
OpenPGP encrypted/signed mail preferred
http://www.thevertigo.com

yes, it's known and it's ok, because luajittex is not different from luatex as luatex is different from pdftex/xetex/etex

(and if it's so, then it is an error).

A quick check could be
\startluacode
if jit==nil then print("=============>This is not luajitTeX") else print("=============>You are running luajitTeX ") end
\stopluacode

of course one can write a global

jit ={} also in luatex.

Another one used in the log is

\startluacode
print("===================>"..string.lower(status.banner))
\stopluacode

and you can search for luajittex .

My wish is that luajittex should be 100% compatible with luatex, but unfortunately there are some differences between lua5.1 used by luajit2.0 and lua5.2
that makes this wish currently impossible to satisfied at engine level --- ConTeXt is smart enough to manage these differences, but you can still write
a lua script that is valid for lua5.2 but not for luajit2.0, see for example

http://lua-users.org/lists/lua-l/2010-03/msg00237.html

Full compatibility between lua5.2 and luajit2.0, for what I see, is not on the top on the Mike Pall's agenda.

--
luigi