Setting variables in LuaTeX texconfig?

Question

The LuaTeX documentation mentions that several variables are accessible by setting a table called texconfig. In particular I want to reduce the output a bit by setting trace_file_names to false. Others have asked for a similar solution but it seems not so easy with other TeX engines. Now LuaTeX offers that choice but I am not sure where and how to set that parameter. The documentation only mentions the table but gives no further hints.

So how can I set or modify the values in the texconfig table in LuaTeX (running under MiKTeX 2.9)?

I tried with the following example but this does not help, maybe this has to be set earlier in the process.

\documentclass{article}

\usepackage{filecontents}

\begin{filecontents*}{word.tex}
hello
\end{filecontents*}

\begin{document}
\directlua{print(texconfig)}
% prints: "table: 02900A90"

\directlua{print(texconfig["trace_file_names"])}
% prints "nil", so value does not exist in table

\directlua{texconfig["trace_file_names"] = false}

\input{word.tex}
% LuaTeX outputs: "(C:/Users/alexander/test/word.tex)"
\end{document}

Answer 1

The boolean variable texconfig.trace_file_names is only in effect when you disable the kpathsea library with texconfig.kpse_init = false.

You can disable the kpathsea library in the ini file called with luatex --lua <inifile> .... See below.

A non working example (it is hard to replace kpathsea in a few lines of code) is like this. Call with lualatex --ini --lua foo.lua test.tex:

test.tex:

Hello
\end

foo.lua:

texconfig.kpse_init = false
texconfig.trace_file_names = false


function kpse.find_file(filename,what)
    return filename
end

local function reader( asked_name )
  local tab = { }
  tab.file = io.open(asked_name)
  tab.reader = function (t)
                  local f = t.file
                  return f:read('*l')
               end
  tab.close = function (t)
                  t.file:close()
              end
  return tab
end


local function find_xxx_file( asked_name )
  return asked_name
end
local function return_asked_name( asked_name )
  return asked_name
end
local function read_font_file( name )
  local f = io.open(name)
  local buf = f:read("*all")
  f:close()
  return true,buf,buf:len()
end
local function find_read_file( id_number,asked_name )
  local file = kpse.find_file(asked_name)
  return file
end
function find_write_file(id_number,asked_name)
  return asked_name
end
local function read_xxx_file(name)
  return nil,nil,0
end

callback.register('open_read_file',reader)

callback.register('find_opentype_file',return_asked_name)
callback.register('find_type1_file',   return_asked_name)
callback.register('find_output_file',  return_asked_name)

callback.register('read_opentype_file',read_font_file)
callback.register('read_type1_file',   read_font_file)

callback.register('find_write_file',find_write_file)

callback.register('find_read_file',find_read_file)

for _,t in ipairs({"find_font_file",'find_vf_file','find_format_file','find_map_file','find_enc_file','find_sfd_file','find_pk_file','find_data_file','find_image_file','find_truetype_file'}) do
  callback.register(t,find_xxx_file)
end
for _,t in ipairs({'read_vf_file','read_sdf_file','read_pk_file','read_data_file','read_font_file','read_map_file'}) do
  callback.register(t, read_xxx_file )
end

It could work if all files are in the local directory, but I haven't tried.