digicompute main env functions

env.lua

-- [function] run code
function digicompute.run_code(code, env)
  if code:byte(1) == 27 then
    return nil, "Binary code prohibited."
  end
  local f, msg = loadstring(code)
  digicompute.log(dump(f)..", "..dump(msg))
  if not f then return false, msg end
  setfenv(f, env)

  -- Turn off JIT optimization for user code so that count
  -- events are generated when adding debug hooks
  if rawget(_G, "jit") then
    jit.off(f, true)
  end

  -- Use instruction counter to stop execution
  -- after 10000 events
  debug.sethook(function()
    return false, "Code timed out!"
  end, "", 10000)
  local ok, ret = pcall(f)
  debug.sethook()  -- Clear hook
  if not ok then return false, ret end
  return true, ret
end

-- [function] run file
function digicompute.run_file(path, env)
  local code = digicompute.builtin.read(path)
  local ok, res = digicompute.run_code(code, env)
  digicompute.log("OK: "..dump(ok)..", "..dump(res))
  return ok, res
end