Expressions for Stereotype Default Value

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AstroJon 2021-3-3

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评论： AstroJon 2021-3-12

In the System Composer Profile Editor, is it possible to use an expression to define the default value of a stereotype? For example, I have a camera hardware component that has focal length and effective aperture size defined as properties with no default values. Then I create a new property called "focal_ratio" and I want to set its default value to "focal_length / effective_aperture". I've tried entering several such expressions in to the default value field but always get an error message stating, "Cannot evaluate the expression..." Is there a particular syntax that will allow this to work?

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Answer 1

Jin Wang 2021-3-12

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Hi,

I understand that you are trying to use syntax to define values and this syntax/expression is using known properties.

Unfortunately, the System Composer Profile Editor does not support syntax based on existent properties. Right now, it only support expressions using contant values, e.g. '7*9+8'. These expressions are treated as string and displayed in the default value edit box. However, they are evaluated and validated in the backend, so you will see a error message showing "Cannot evaluate the expression" for your case. I have forwarded your concerns to my colleague and we will discuss about supporting expressions containing existent properties.

Thanks,

Jin

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AstroJon 2021-3-12

That's unfortunate, but thank you for addressing it as a functional need. I think having such capability would make System Composer much more powerful.

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