local isDev = true  -- set this for your own development environments, it will make the BSOD print a line number.

local function main(argc, argv)
  if argc ~= 0 then
        if argc == 1 then
          if argv[1] == "-help" then
                print("Valid arguments -help -test")
                return true -- we want to exit but not trigger the BSOD for something this trivial
          elseif argv[1] == "-test" then
                print("Tested, now running")
          else
                print("Invalid argument, "..argv[1].." run with -help to see valid arguments")
                return true -- we want to exit but not trigger the BSOD for something this trivial
          end
        else
          print("This program only supports 1 argument not "..argc)
          return true -- we want to exit but not trigger the BSOD for something this trivial
        end
  end

  -- function calls and main code body here

  return true
end

local ok, err = pcall(main, #({...}), {...})

if not ok then
  -- for the following 2 functions are from my Extended String Library...
  local split = function(str, pat) local t = {} local fpat = "(.-)"..pat local last_end = 1local s, e, cap = str:find(fpat, 1) while s do if s ~= 1 or cap ~= "" then table.insert(t,cap) end last_end = e + 1 s, e, cap = str:find(fpat, last_end) end if last_end <= #str then cap = str:sub(last_end) table.insert(t, cap) end return t end
  local trim = function(str) return (str:gsub("^%s*(.-)%s*$", "%1")) end

  -- localize these as they are only used here
  local setColors = function(bg, txt) if not (term.isColor and term.isColor()) then return false end if txt then term.setTextColor(txt) end if bg then term.setBackgroundColor(bg) end end
  local clear = function(col) if col then term.setBackgroundColor(col) end term.clear() end
  local cwrite = function(msg, y, offset) local sw,sh = term.getSize() term.setCursorPos(sw/2-#msg/2, (y or (sh/2)) + (offset or 0)) write(msg) end
  local errHeader = function(text, y, centre) setColors(colors.white, colors.blue) if centre then cwrite(text, y) else term.setCursorPos(1,y) print(text) end setColors(colors.blue, colors.white) end
  local printMsg = function(text, y) term.setCursorPos(1,y) print(text) end
  local waitForKey = function() while true do local e,k=os.pullEventRaw("key") if k == 28 or k == 156 then break end end end
  local err = split(err,":")
  local sw,sh = term.getSize()

  clear(colors.blue)

  -- the error headers
  errHeader(" ERROR : "..( err[#err-2] and string.upper(err[#err-2]) or "<UNKNOWN>").." ", 2, true)
  errHeader(" Error Description ", 7, false)
  errHeader(" Reporting the Issue ", sh-7, false)

  -- BSOD content
  printMsg("An error has occurred during runtime with \'"..(err[#err-2] or "<unknown>").."\' and the program has ceased working.", 4)
  printMsg(trim((isDev and "Line "..(err[#err-1] and err[#err-1] or "<unknown>")..":" or "")..err[#err]) or "<No error message supplied>",9)
  printMsg("If this problem persists please try updating the program with '-update' and if the problem still persists report the issue with '-report'",sh-5)

  cwrite("Press enter to quit...",sh-1)
  waitForKey()

  term.clear(colors.black)
  term.setCursorPos(1,1)
end