[Edu-sig] turtle: properties instead of setters/getters ?

[Andre Roberge]

On Mon, Apr 27, 2015 at 12:19 PM, Jurgis Pralgauskis <
jurgis.pralgauskis at gmail.com> wrote:

> Hi,
>
> turtle module is nice way to introduce to Python,
> but, if I want to increase x by 10, I have to write
>
> t.setx( t.xcor() + 1)
>
> which is uglier (and not beginner friendly) than common:
> t.x = t.x + 1
>
> beginners tend to forget () after xcor and so on...
>
> This could be achieved with  several property
> <https://docs.python.org/3/library/functions.html#property>/decorator
> lines
> Would it be possible for Py 3.5? :)
>
>
I doubt very much that anything is going to happen with the official Turtle
module unless the person that actually wrote it decides it's worth looking
into.

Following a suggestion you made on this list, I submitted a patch (
http://bugs.python.org/issue23660) about 6 weeks ago and no one has looked
into it as far as I can tell.

You could possibly write your own Turtle module, as a wrapper to the
official one, using properties the way you mention.



>
> ps.: I teach programming games,
> and more robust expressions (for collision checking) would look cleaner:
> if ball.x-5 > box.x-10   and  ball.x+5 < box.x+10:
>      ball.x =100
>
> instead of
> if ball.xcor()-5 > box.xcor()-10   and  ball.xcor()+5 < box.xcor()+10:
>      ball.setx( 100 )
>
Yes, I prefer the first style too.

>
> pps.:
> I don't know how would default turtle instance behave
> could I then write     x = x + 1
> instead of          setx( xcor() + 1)
> ?
>

This would not be possible: x would just be a variable, with no relation to
a given turtle. At the very least, one would need to call some update()
function which could look at the values of the variables in locals() and
proceed from there....  But I think that this would be counter-intuitive
and not a good way to teach about Python.

André

>
>
> --
> Jurgis Pralgauskis
> tel: 8-616 77613;
> Don't worry, be happy and make things better ;)
> http://galvosukykla.lt
>
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