[Gambas-user] INC and DEC on BOOLEAN data...

[Benoit Minisini]

On dimanche 11 mai 2008, Stephen Bungay wrote:
> Benoit Minisini wrote:
> > On dimanche 11 mai 2008, you wrote:
> >>    IMHO this is broken thinking. It might be a little more typing to use
> >> VarName = NOT VarName but it is decidedly more transparent as to what
> >> datatype 'VarName' is and what is being done to it.
> >>
> >> Success = Not Success
> >>
> >> vs
> >>
> >> INC(Success)
> >>
> >> DEC(Success)
> >>
> >>    In the first example it is very clear what is being done, even when
> >> Hungarian notation is not being used, whereas in the second example all
> >> that is clear is that a value is being incremented or decremented. INC
> >> and DEC implies a change in direction (up or down) to a numeric value,
> >> while NOT implies a change in state, which is more analogous to a
> >> toggle.
> >>
> >>    I think, and perhaps I'm wrong on this, that a 'data type mismatch'
> >> error is the proper response to those trying to INC or DEC a boolean.
> >>   Sorry, I just had to reply, when I see things like this it makes me
> >> cringe, like someone dragging their fingernails on a blackboard makes me
> >> cringe.
> >>
> >>
> >> Kindest regards
> >> Stephen Bungay
> >
> > Boolean and Integer values can be converted into each other in Gambas:
> >
> > True -> -1
> > False -> 0
> >
> > 0 -> False
> > Any other value -> True
> >
> > Incrementing or decrementing a boolean variable actually incremented or
> > decremented its integer converted value.
> >
> > INC False -> Inc 0 -> 1 -> True
> > INC True -> Inc -1 -> 0 -> False
> >
> > DEC False -> Dec 0 -> -1 -> True
> > DEC True -> Dec -1 -> -2 -> True ?
> >
> > Weird, so this was fixed in Gambas 2.6, so that DEC True -> False.
> > Otherwise, you will have to remember that INC toggle, but not DEC. I
> > found that too complex for my own brain.
> >
> > This is coherent with the common behaviour of Gambas. I mean you can INC
> > or DEC dates too, as Date and Float can be converted to each other.
> >
> > You can ignore this feature if you don't like it. Anyway, it cannot be
> > removed in 2.x for backward compatibility reasons.
> >
> > I could remove it in 3.0, and replace it by a NOT instruction that would
> > do the same thing only for booleans:
> >
> > NOT MyMenu.Checked ' for example
> >
> > Regards,
>
>    Yes, just because the feature is there doesn't mean the programmer
> (me in this case) has to use it. Or, as I've become fond of saying,
> 'Just because something CAN be done a certain way doesn't mean it SHOULD
> be done that way'.
>    INC and DEC makes sense on Dates since it implies a direction, into
> the future or back in the past, as opposed to the state change of On or
> Off, True or False a boolean value implies.
>
>    Personally I think I'll just stay with the already implemented BASIC
> syntax and use;
>
> MyMenu.Checked = NOT MyMenu.Checked
>
>    as it is clear as to it's intent. With typeahead already working to
> reduce typing there is little in the way of extra burden to the
> programmer as far as keystrokes go.
>
> IMHO, creating a 'NOT' instruction confuses things further since;
>
> MyMenu.Checked = Not MyMenu.Checked
>
> and
>
> NOT MyMenu.Checked
>
>    would produce the same result, however the latter looks more like an
> incomplete conditional than an assignment statement.
>
>    IMHO it is a good idea to Deprecate the INC and DEC on BOOL datatypes
> in Gambas 3.0.
>
>    GAMBAS is your baby Benoit, and you have done the Linux community a
> great service with it. I really have no place making any suggestions and
> thank you for taking the time to read my thoughts on the subject,
> however naive they might be.
>
> Stephen Bungay
>

No problem. But if you are the only one people that is disturbed by this 
semantic, maybe I won't remove it. On the other hand, if many many people 
cry, I will!

-- 
Benoit Minisini