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Validating namespace imports? [message #1446054]

Thu, 16 October 2014 09:43

Stephan Herrmann

Messages: 1853
Registered: July 2009

Senior Member

Has anyone written a validator that would flag unresolved and/or unused namespace imports?

I wonder if normalizers could keep track of which imports have been used during resolution, but it seems that the necessary information is too far spread. Perhaps an EObjectDescription would need a link back to the import whose normalizer was used to create it? Then successful resolution using a particular EObjectDescription could go back and mark the import as used.

If we could identify unused imports, we could then perform more expensive search to distinguish unresolved from plain unused.

Nothing of this looks trivial to me (if performance is taken into account), hence the question: does anything like this exist somewhere?

TIA,
Stephan

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Re: Validating namespace imports? [message #1446099 is a reply to message #1446054]

Thu, 16 October 2014 11:00

Ed Willink

Messages: 7655
Registered: July 2009

Senior Member

Hi

It is possible to use OCL to define custom validation rules that can be
loaded into unsuspecting EMF applications.

The Complete OCL tutorial in the OCL documentation demonstrates how a
couple of style rules can be added to Xtext.

Regards

Ed Willink

On 16/10/2014 10:43, Stephan Herrmann wrote:
> Has anyone written a validator that would flag unresolved and/or unused
> namespace imports?
>
> I wonder if normalizers could keep track of which imports have been used
> during resolution, but it seems that the necessary information is too
> far spread. Perhaps an EObjectDescription would need a link back to the
> import whose normalizer was used to create it? Then successful
> resolution using a particular EObjectDescription could go back and mark
> the import as used.
>
> If we could identify unused imports, we could then perform more
> expensive search to distinguish unresolved from plain unused.
>
> Nothing of this looks trivial to me (if performance is taken into
> account), hence the question: does anything like this exist somewhere?
>
> TIA,
> Stephan
>

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Re: Validating namespace imports? [message #1446130 is a reply to message #1446099]

Thu, 16 October 2014 12:02

Stephan Herrmann

Messages: 1853
Registered: July 2009

Senior Member

Ed Willink wrote on Thu, 16 October 2014 13:00

Hi

It is possible to use OCL to define custom validation rules that can be
loaded into unsuspecting EMF applications.

The Complete OCL tutorial in the OCL documentation demonstrates how a
couple of style rules can be added to Xtext.

Thanks for the suggestion. For this particular situation, can you say a word on performance? My intuition is, that anything that's not closely integrated with the way how Xtext evaluates imports will be prohibitively slow in projects with many hundrets of models, since each validation for an individual import will have to search the entire universe of model elements, no?

In particular, it would be cool to have a strategy that is fast without requiring an index, since in some cases I'd want to run this validation at application runtime (i.e. outside Eclipse).

thanks,
Stephan

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Re: Validating namespace imports? [message #1446139 is a reply to message #1446130]

Thu, 16 October 2014 12:18

Ed Willink

Messages: 7655
Registered: July 2009

Senior Member

Hi

An add-on to Xtext certainly won't compare in performance with something
integrated.

Particularly not if execution uses an interpreted approach.

For an occasional interactive how are we doing, the OCL approach should
work fine. If you want it integrated in a frequent auto-build, you may
need to work harder.

Regards

Ed Willink

On 16/10/2014 13:02, Stephan Herrmann wrote:
> Ed Willink wrote on Thu, 16 October 2014 13:00
>> Hi
>>
>> It is possible to use OCL to define custom validation rules that can
>> be loaded into unsuspecting EMF applications.
>>
>> The Complete OCL tutorial in the OCL documentation demonstrates how a
>> couple of style rules can be added to Xtext.
>
>
> Thanks for the suggestion. For this particular situation, can you say a
> word on performance? My intuition is, that anything that's not closely
> integrated with the way how Xtext evaluates imports will be
> prohibitively slow in projects with many hundrets of models, since each
> validation for an individual import will have to search the entire
> universe of model elements, no?
>
> In particular, it would be cool to have a strategy that is fast without
> requiring an index, since in some cases I'd want to run this validation
> at application runtime (i.e. outside Eclipse).
>
> thanks,
> Stephan
>

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Re: Validating namespace imports? [message #1446158 is a reply to message #1446054]

Thu, 16 October 2014 12:46

Sebastian Zarnekow

Messages: 3118
Registered: July 2009

Senior Member

Hi Stephan,

yes, someone has already implemented such a validator for customers. And
yes, the approach was pretty close to what you describe wrt to
EObjectDescriptions that mark imports as used during linking.

In short: what you describe works exactly like that. No, the code is not
publicly available, though.

Best,
Sebastian
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