[luatex] Lua access to pdf back end variables

[Joseph Wright]

Hello all,

With the v0.85 release, pdfTeX primitives such as \pdfdecimaldigits are
removed with TeX access documented using for example

    \pdfvariable decimaldigits

Currently, the documentation still lists the Lua access routes as e.g.
tex.pdfdecimaldigits. Is this likely to change? I'm trying to set up
some code to work with LuaTeX both before and after this change but
without having to globally enable a load of names then tidy them up. Lua
access seems to be the way to do this *but* I'm not sure if I need

    local decimaldigits = tex.pdfdecimaldigits

or

     local decimaldigits = tex.decimaldigits or tex.decimaldigits

or ...

Joseph