Re: no return value vs. nil return value(s)
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- Subject: Re: no return value vs. nil return value(s)
- From: Dirk Laurie <dpl@...>
- Date: 2011年9月12日 08:17:20 +0200
On Mon, Sep 12, 2011 at 01:12:47AM +0200, Lorenzo Donati wrote:
> Yes, that's the same feeling I have by default. But the idea to exploit
> such a feature came to me just from the behaviour of some library
> functions, which *do* make a difference:
>
> --------------------------------------------
> local function f() return end
> local function g() return nil end
>
> assert( f() ) --> bad argument #1 to 'assert' (value expected)
> assert( g() ) --> assertion failed!
>
> table.insert( t, f() ) --> wrong number of arguments to 'insert'
> table.insert( t, g() ) -->ok
>
In both cases, the behaviour seems not to be planned for, but
not sufficiently obnoxious to justify testing for it.
> So even if I agree it is a subtle difference, the fact that the
> difference is exposed through the library seems to suggest that it is a
> legitimate technique.
>
The fact that a doctor treats certain conditions by injecting cocaine
does not mean that everybody can legitimately do so.
Dirk