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Best place to create an instance of an external referenced emf model element? [message #1782950]

Mon, 05 March 2018 14:36

Chris X

Messages: 60
Registered: November 2017

Member

Hi guys,

in my language it's possible to create an instance of an model element that is defined in a external emf model.

For example the external model has a book with the name "XY" and with the attribute pages = 230.

Now in my language it should be possible to create a copy of such a book and to access the attributes

set books::book<XY> as bookCopy
bookCopy.pages = 120

What is the best way to implement this and where? So at the and I need a dynamic created model that holds all these dynamically create books.

It would be nice to get a list of the main steps to implement such a feature.

Many thanks and have a nice day

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Re: Best place to create an instance of an external referenced emf model element? [message #1782953 is a reply to message #1782950]

Mon, 05 March 2018 15:07

Chris X

Messages: 60
Registered: November 2017

Member

Additionally I need the following behavior:

set books::book<XY> as bookCopy

var x = bookCopy.pages+4 
// x has the value 234
bookCopy.pages = 12
// bookCopy.pages has the value 12
x= 100
// x has the value 100
x = x + bookCopy.pages;  // At this line x on the right side of the assignment has the value 100.

How do I now what's the current value of x (depending on the line)? I think it's the job of the interpreter or an evaluator. But is there in example how to implement such an evaluator?

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Re: Best place to create an instance of an external referenced emf model element? [message #1782954 is a reply to message #1782953]

Mon, 05 March 2018 15:24

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

do you know the concept of an IDerived state Computer?
and the place would be slots 1 to n in resource.contents.

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Best place to create an instance of an external referenced emf model element? [message #1782956 is a reply to message #1782954]

Mon, 05 March 2018 15:37

Chris X

Messages: 60
Registered: November 2017

Member

Yes okay it's also the DerivedState-Computer. Then I'm happy ;)

Can you tell be the use-case of the DerivedState-Computer. So when should I use it and when not? This is currently not clear for me.

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