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Xtend2 - sorting by a function [message #668016]

Tue, 03 May 2011 12:09

Andrew Clark

Messages: 23
Registered: June 2010

Junior Member

Using the MyDsl example in Xtext 2, I have written the following Xtend

class MyDslGenerator implements IGenerator {
	
	override void doGenerate(Resource resource, IFileSystemAccess fsa) {
		for(model: resource.allContentsIterable.filter(typeof(Model))) {
			fsa.generateFile("example.txt", model.hello)
		}
	}
	
	hello (Model m) {
		''' 
		Longest is «m.longest»
		'''
	}

	longest(Model m) {
		m.greetings.sortBy(e|e.length).last.name
	}

	longest2(Model m) {
		m.greetings.map(e|e.length).sort.last
	}
	
	int length(Greeting g) {
		g.name.length
	}
	
}

When this runs I get

Exception in thread "main" java.lang.IllegalArgumentException: The 'no duplicates' constraint is violated
	at org.eclipse.emf.common.util.AbstractEList.set(AbstractEList.java:268)
	at org.eclipse.emf.common.util.AbstractEList$EListIterator.doSet(AbstractEList.java:963)
	at org.eclipse.emf.common.util.AbstractEList$EListIterator.set(AbstractEList.java:941)
	at java.util.Collections.sort(Unknown Source)
	at org.eclipse.xtext.xbase.lib.ListExtensions.sortBy(ListExtensions.java:85)
	at org.xtext.example.mydsl.generator.MyDslGenerator.longest(MyDslGenerator.java:46)
	at org.xtext.example.mydsl.generator.MyDslGenerator.hello(MyDslGenerator.java:32)
	at org.xtext.example.mydsl.generator.MyDslGenerator.doGenerate(MyDslGenerator.java:24)
	at org.xtext.example.mydsl.generator.Main.runGenerator(Main.java:63)
	at org.xtext.example.mydsl.generator.Main.main(Main.java:32)

alternatively I can try the longest2 function and get

Exception in thread "main" java.lang.UnsupportedOperationException
	at java.util.AbstractList.set(Unknown Source)
	at java.util.AbstractList$ListItr.set(Unknown Source)
	at java.util.Collections.sort(Unknown Source)
	at org.eclipse.xtext.xbase.lib.ListExtensions.sort(ListExtensions.java:44)
	at org.xtext.example.mydsl.generator.MyDslGenerator.longest2(MyDslGenerator.java:61)
	at org.xtext.example.mydsl.generator.MyDslGenerator.hello(MyDslGenerator.java:32)
	at org.xtext.example.mydsl.generator.MyDslGenerator.doGenerate(MyDslGenerator.java:24)
	at org.xtext.example.mydsl.generator.Main.runGenerator(Main.java:63)
	at org.xtext.example.mydsl.generator.Main.main(Main.java:32)

Is this a bug (this worked in Xtend 1)?

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Re: Xtend2 - sorting by a function [message #668036 is a reply to message #668016]

Tue, 03 May 2011 13:28

Sven Efftinge

Messages: 1823
Registered: July 2009

Senior Member

It's because (currently) the sort functions do modify the passed list.
EMF puts certain constraints on the list which are validated during the
sort operation. I think we should change that and return a new list
instead and leave the old one unmodified.
Please open a bugzilla.

Thanks,
Sven

Am 5/3/11 2:09 PM, schrieb Andrew Clark:
> Using the MyDsl example in Xtext 2, I have written the following Xtend
>
> class MyDslGenerator implements IGenerator {
>
> override void doGenerate(Resource resource, IFileSystemAccess fsa) {
> for(model: resource.allContentsIterable.filter(typeof(Model))) {
> fsa.generateFile("example.txt", model.hello)
> }
> }
>
> hello (Model m) {
> ''' Longest is «m.longest»
> '''
> }
>
> longest(Model m) {
> m.greetings.sortBy(e|e.length).last.name
> }
>
> longest2(Model m) {
> m.greetings.map(e|e.length).sort.last
> }
>
> int length(Greeting g) {
> g.name.length
> }
>
> }
>
>
> When this runs I get
>
>
> Exception in thread "main" java.lang.IllegalArgumentException: The 'no
> duplicates' constraint is violated
> at
> org.eclipse.emf.common.util.AbstractEList.set(AbstractEList. java:268)
> at
> org.eclipse.emf.common.util.AbstractEList$EListIterator.doSe t(AbstractEList.java:963)
>
> at
> org.eclipse.emf.common.util.AbstractEList$EListIterator.set( AbstractEList.java:941)
>
> at java.util.Collections.sort(Unknown Source)
> at
> org.eclipse.xtext.xbase.lib.ListExtensions.sortBy(ListExtens ions.java:85)
> at
> org.xtext.example.mydsl.generator.MyDslGenerator.longest(MyD slGenerator.java:46)
>
> at
> org.xtext.example.mydsl.generator.MyDslGenerator.hello(MyDsl Generator.java:32)
>
> at
> org.xtext.example.mydsl.generator.MyDslGenerator.doGenerate( MyDslGenerator.java:24)
>
> at org.xtext.example.mydsl.generator.Main.runGenerator(Main.jav a:63)
> at org.xtext.example.mydsl.generator.Main.main(Main.java:32)
>
>
>
> alternatively I can try the longest2 function and get
>
>
> Exception in thread "main" java.lang.UnsupportedOperationException
> at java.util.AbstractList.set(Unknown Source)
> at java.util.AbstractList$ListItr.set(Unknown Source)
> at java.util.Collections.sort(Unknown Source)
> at
> org.eclipse.xtext.xbase.lib.ListExtensions.sort(ListExtensio ns.java:44)
> at
> org.xtext.example.mydsl.generator.MyDslGenerator.longest2(My DslGenerator.java:61)
>
> at
> org.xtext.example.mydsl.generator.MyDslGenerator.hello(MyDsl Generator.java:32)
>
> at
> org.xtext.example.mydsl.generator.MyDslGenerator.doGenerate( MyDslGenerator.java:24)
>
> at org.xtext.example.mydsl.generator.Main.runGenerator(Main.jav a:63)
> at org.xtext.example.mydsl.generator.Main.main(Main.java:32)
>
>
> Is this a bug (this worked in Xtend 1)?
>

--
Need professional support for Xtext or other Eclipse Modeling technologies?
Go to: http://xtext.itemis.com
Twitter : @svenefftinge
Blog : http://blog.efftinge.de

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Re: Xtend2 - sorting by a function [message #668038 is a reply to message #668036]

Tue, 03 May 2011 13:36

Sebastian Zarnekow

Messages: 3118
Registered: July 2009

Senior Member

Hi Sven, hi Andrew,

since it's well documented (since M7) which functions modify the passed
list and which create new copies of the input, I'm inclined to not
change the behavior of sort. Otherwise it's hardly possible to sort an
existing list in a convenient way with Xtend.

Regards,
Sebastian
--
Need professional support for Eclipse Modeling?
Go visit: http://xtext.itemis.com

Am 03.05.11 15:28, schrieb Sven Efftinge:
> It's because (currently) the sort functions do modify the passed list.
> EMF puts certain constraints on the list which are validated during the
> sort operation. I think we should change that and return a new list
> instead and leave the old one unmodified.
> Please open a bugzilla.
>
> Thanks,
> Sven
>
>
> Am 5/3/11 2:09 PM, schrieb Andrew Clark:
>> Using the MyDsl example in Xtext 2, I have written the following Xtend
>>
>> class MyDslGenerator implements IGenerator {
>>
>> override void doGenerate(Resource resource, IFileSystemAccess fsa) {
>> for(model: resource.allContentsIterable.filter(typeof(Model))) {
>> fsa.generateFile("example.txt", model.hello)
>> }
>> }
>>
>> hello (Model m) {
>> ''' Longest is «m.longest»
>> '''
>> }
>>
>> longest(Model m) {
>> m.greetings.sortBy(e|e.length).last.name
>> }
>>
>> longest2(Model m) {
>> m.greetings.map(e|e.length).sort.last
>> }
>>
>> int length(Greeting g) {
>> g.name.length
>> }
>>
>> }
>>
>>
>> When this runs I get
>>
>>
>> Exception in thread "main" java.lang.IllegalArgumentException: The 'no
>> duplicates' constraint is violated
>> at
>> org.eclipse.emf.common.util.AbstractEList.set(AbstractEList. java:268)
>> at
>> org.eclipse.emf.common.util.AbstractEList$EListIterator.doSe t(AbstractEList.java:963)
>>
>> at
>> org.eclipse.emf.common.util.AbstractEList$EListIterator.set( AbstractEList.java:941)
>>
>> at java.util.Collections.sort(Unknown Source)
>> at
>> org.eclipse.xtext.xbase.lib.ListExtensions.sortBy(ListExtens ions.java:85)
>> at
>> org.xtext.example.mydsl.generator.MyDslGenerator.longest(MyD slGenerator.java:46)
>>
>> at
>> org.xtext.example.mydsl.generator.MyDslGenerator.hello(MyDsl Generator.java:32)
>>
>> at
>> org.xtext.example.mydsl.generator.MyDslGenerator.doGenerate( MyDslGenerator.java:24)
>>
>> at org.xtext.example.mydsl.generator.Main.runGenerator(Main.jav a:63)
>> at org.xtext.example.mydsl.generator.Main.main(Main.java:32)
>>
>>
>>
>> alternatively I can try the longest2 function and get
>>
>>
>> Exception in thread "main" java.lang.UnsupportedOperationException
>> at java.util.AbstractList.set(Unknown Source)
>> at java.util.AbstractList$ListItr.set(Unknown Source)
>> at java.util.Collections.sort(Unknown Source)
>> at
>> org.eclipse.xtext.xbase.lib.ListExtensions.sort(ListExtensio ns.java:44)
>> at
>> org.xtext.example.mydsl.generator.MyDslGenerator.longest2(My DslGenerator.java:61)
>>
>> at
>> org.xtext.example.mydsl.generator.MyDslGenerator.hello(MyDsl Generator.java:32)
>>
>> at
>> org.xtext.example.mydsl.generator.MyDslGenerator.doGenerate( MyDslGenerator.java:24)
>>
>> at org.xtext.example.mydsl.generator.Main.runGenerator(Main.jav a:63)
>> at org.xtext.example.mydsl.generator.Main.main(Main.java:32)
>>
>>
>> Is this a bug (this worked in Xtend 1)?
>>
>
>

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Re: Xtend2 - sorting by a function [message #668047 is a reply to message #668038]

Tue, 03 May 2011 14:10

Andrew Clark

Messages: 23
Registered: June 2010

Junior Member

Hi Sebastian,

If the sort functionality is not changed then how should I write the Xtend code in my example ?

BTW: Which documentation are you talking about, the Java doc in ListExtensions ?

regards,

Andrew

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Re: Xtend2 - sorting by a function [message #668052 is a reply to message #668047]

Tue, 03 May 2011 14:32

Sebastian Zarnekow

Messages: 3118
Registered: July 2009

Senior Member

Hi Andrew,

we discussed this offline and I filed this ticket to describe the results:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=344584

Regards,
Sebastian
--
Need professional support for Eclipse Modeling?
Go visit: http://xtext.itemis.com

Am 03.05.11 16:10, schrieb Andrew Clark:
> Hi Sebastian,
> If the sort functionality is not changed then how should I write the
> Xtend code in my example ?
> BTW: Which documentation are you talking about, the Java doc in
> ListExtensions ?
>
> regards,
>
> Andrew
>
>
>

Report message to a moderator