Re: A little bit about nothing (was Re: Empty? No. Array? No. Has? Yes.)
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- Subject: Re: A little bit about nothing (was Re: Empty? No. Array? No. Has? Yes.)
- From: Sean Conner <sean@...>
- Date: Wed, 3 Jul 2013 15:45:30 -0400
It was thus said that the Great Andrew Starks once stated:
> This does not work though. Your version of something will always
> report something, unless something is called:
>
> function something(...)
> if select('#',...) == 0 then
> return false
> else
> local mary = ...
> return true
> end
> end
>
> print(something())
> --false, good
>
> local baz
> print(something(baz))
> --true, good
>
> print(something(foo))
> --true, bad
x = {}
print(something(x[1]))
--true, good (I assume)
print(something(x.foo))
--true, good (I assume)
Interesting. I think what's happening here is that during compilation,
Lua realizes that foo does not exist as a global variable, and thus, does
not generate a load statement for the paramter to something() (that would be
my guess, given the behavior).
But my intent with
something(mary) --[[ something about mary ]] end
is that, *as given* (with a formal parameter) there is no way for something
to determine if something was passed. It can if you change the formal
paramter to a vararg.
-spc