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Is this an ATL bug? [message #1852887]

Thu, 09 June 2022 14:48

M M

Messages: 4
Registered: February 2022

Junior Member

Hi,

I have a simple transformation:

module Transformation;
create OUT : TargetMM from IN : SourceMM;

rule Source2Target {
	from
		source : SourceMM!Source
	to
		target : TargetMM!Target (
			source <- source,
			target <- target
		)
}

When I run this on some sample model, I get some strange behaviour that does not match up with the transformation. For example, a sample output may look like:

<?xml version="1.0" encoding="ISO-8859-1"?>
<target:Target xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:target="target" target="/" source="/"/>

You can see that target="/", and also source="/". This means that both of those properties are referencing the same element. To me, this looks like the source property is completely incorrect. I would expect the source property points to the original value in the input model with the use of an inter-model reference. Instead, it simply points to an element in the output model.

This doesn't just happen in this toy example. I have a more complex project where the output is a third model containing links between source/target elements. However both the source and target element also always reference the target element. This makes the traces effectively useless because there's no way to store a reference to the source element.

I've enabled inter-model references. Is this an ATL bug?

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Re: Is this an ATL bug? [message #1852892 is a reply to message #1852887]

Thu, 09 June 2022 15:57

Burak Karaduman

Messages: 84
Registered: July 2018

Member

Hi,

I have a similar issue. Could you help us with this?

Thank you all.

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Re: Is this an ATL bug? [message #1852893 is a reply to message #1852892]

Thu, 09 June 2022 17:04

Dennis Wagelaar

Messages: 581
Registered: September 2012
Location: Belgium

Senior Member

The binding operator '<-' performs implicit tracing from source to target elements. Therefore, when you bind a transformed source element to some property, it is replaced by its target counterpart when assigning it.

If you want to prevent this behaviour, you can use the assignment operator '<:='.

Cheers,
Dennis

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Re: Is this an ATL bug? [message #1852895 is a reply to message #1852893]

Thu, 09 June 2022 17:21

M M

Messages: 4
Registered: February 2022

Junior Member

Hi Dennis,

Thanks for the reply. When using the assignment operator <:=, I get the exact same erroneous result. Here's the transformation with the applied change, though it doesn't make a difference:

module Transformation;
create OUT : TargetMM from IN : SourceMM;

rule Source2Target {
	from
		source : SourceMM!Source
	to
		target : TargetMM!Target (
			source <:= source,
			target <- target
		)
}

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