Re: [ANN] Lua 5.3.0 (final) now available

[tomas <tomas@...>]

Hi Roberto and Jorge

> > If the function was just returning nothing, that would be ok. But
> > in fact it is returning an error indicator followed by the error
> > message. To mix an error indicator with an absent value is what 
> > bothers
> > me.
But what value could be that error indicator?  Or you thought about 
changing the whole model to something like exception handling 
constructions?  In that case the error indicator would be internal to 
the VM no?

> But nil is not a value.
Yes.  I would call it a non-value (something like NaN ?)

> And if a
> application has some other meaning for nil besides "absence of value",
> perhaps something from the application domain, then I think said
> application is badly designed. In that sense, in application domain,
> nil is not a "perfectly valid return"
In SQL, NULL is that kind of value.  And the mapping of NULL to nil is 
quite natural, although sometimes the programmer have to take care (for 
instance, not to make a query that could result in NULL at the first 
column of a valid row).

In fact, I think part of this discussion also applies to the domain of 
database languages such as SQL.

Regards,
Tomás