[etoys-dev] Slots without watchers

K. K. Subramaniam subbukk at gmail.com
Mon Sep 28 19:17:48 EDT 2009

On Tuesday 29 Sep 2009 1:36:53 am Ricardo Moran wrote:
> I don't see why a function shouldn't have a readout. It returns a value,
> and IMHO all useful values should have readouts. This includes bearingTo,
> distanceTo, isOverColor, colorSees, overlaps, overlapsAny, and so on. I
> know some of them can't have readouts because of performance issues but if
> bearingTo is not the case I think it should have one.
I expect watchers are only for variables/properties. With computations, one is 
not sure about side effects. One can always create a variable and use a script 
to track the changes through this variable.

There is a bigger issue that will confuse young kids. The viewer has three 
types of slots - commands, variables and computations but they map to only two 
types of menu buttons. The "observation" category also includes variables with 
watchers, so not all relationships are computed :-(.

How about using round edges or changing color of computed tiles?


More information about the etoys-dev mailing list