Re: Safe navigation operator

[Roberto Ierusalimschy <roberto@...>]

> The problem happens (for example) when you use multiple level tables
> to store configurations. For example, you store something like:
> 	config.network.server.url = "xxx"
> If the parameter is optional, or if you do not want bad surprise, when
> you want to use it you need to write:
> 	if confg.network and config.network.server and config.network.server.url then
> 		dosomething(config.network.server.url)
> 	End

What about this?  (untested code...)

local emptytable = {}
local function Opt (t) return t or emptytable end

  if config.Opt(network).Opt(server).url then
    dosomething(config.network.server.url)
  End

-- Roberto