Universal lua tostring

Universal tostring (also available here)

function table_print (tt, indent, done)
done = done or {}
indent = indent or 0
if type(tt) == "table" then

 local sb = {}
 for key, value in pairs (tt) do
   table.insert(sb, string.rep (" ", indent)) -- indent it

   if type (value) == "table" and not done [value] then
     done [value] = true

     table.insert(sb, "{\n");
     table.insert(sb, table_print (value, indent + 2, done))
     table.insert(sb, string.rep (" ", indent)) -- indent it
     table.insert(sb, "}\n");
   elseif "number" == type(key) then

     table.insert(sb, string.format("\"%s\"\n", tostring(value)))
   else
     table.insert(sb, string.format("%s = \"%s\"\n", tostring (key), tostring(value)))
    end

 end
 return table.concat(sb)
else
 return tt .. "\n"
end

end

function to_string( tbl )
 if  "nil"       == type( tbl ) then
     return tostring(nil)
 elseif  "string" == type( tbl ) then
     return tbl
 elseif  "table" == type( tbl ) then
     return table_print(tbl)
 else
     tostring(tbl)
 end
end

Example

 print(to_string({"Lua",user="Mariacher",{{co=coroutine.create(function() end),{number=12345.6789}},
 func=function() end}, boolt=true}))

This prints

"Lua"
{
{
 {
   number = "12345.6789"
 }
 co = "thread: 0212B848"
}
func = "function: 01FC7C70"
}
boolt = "true"

user = "Mariacher"