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

[Paul Horechuk]

On May 11, 2008 11:45:44 am Benoit Minisini wrote:
> 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 
2.6http://www.directdial.com/LX.AJA0X.226.html, 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!
I have to side with Stephen on this. Allowing INC and DEC on Boolean is just 
plain bad form. What's next, INC(Char) or INC(File)?



-- 
-- Paul Horechuk
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