Processing of Command Error: Issue Found!

rgoldrich shared this question 2 years ago
Needs Answer

For the past couple of days I have seen the "Processing of Command" error when opening a GGB file, and then finding that my custom tool did not work. Well, I figured out *my* problem and maybe this can be a help to others. So first I'll describe the issue / work around, and then I have a question about the same subject.

1. The attached GGB file contains a tool called "TestTool" that draws a simple vector at an angle 'beta'. It also has two buttons, each running a simple script that zeros out 'beta'.

2. Running 'Good Script' sets the angle beta to zero *with the degrees symbol after it.

Running 'Bad Script' sets the angle to beta to zero... with no degrees symbol.

3. If you run 'Good Script' and then re-save the file, you will not get an error.

But if you run 'Bad Script' and re-save the file, you will get the "processing of command" error. What happens is that the 'Bad Script' converts 'beta' to a normal scalar (i.e. no degrees symbol after it), while the TestTool (for some reason) is expecting only an angle in degrees. This is the issue. The fix is to be consistent with your angles (i.e. degrees vs. radians).

I don't know enough about the Geogebra internals to call this a but. Essentially, Geogebra is being very strict -- and that's not necessarily bad, but given the lack of warning messages it makes these issues very difficult to track.

So this brings me to my question: I get why *constructed* angles (angles constructed by points and lines) are classified as 'angles', but I'm not sure why an angle that is defined numerically is not regarded simply as a scalar -- and treated as an angle when used as such (e.g. in a trig function). This is obviously a design / philosophy decision taken a long time ago. Still, it doesn't sit right with me... or maybe I'm missing something.

Anyhow, I hope this helps some of the issues you might be seeing.


PS: I am amazed daily by the capabilities of Geogebra and I have the highest regards for the founder and contributors.

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