[texhax] Question about cwebmac.tex

[David Carlisle]

The question is how to tell LuaTeX to leave catcode of backslash 12 if
it was 12 when lua was called

It _is_ 12, but while   \( is a bracket in a pdf string it is first
interpreted as a lua string
(where catcodes are meaningless)  so you need to lua-escape the string so

from tex \luaescapestring or or some lua string replace depending
where you do it.

David