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How to declare type of empty collection in OCL? [message #61231]

Tue, 14 November 2006 10:25

Tord Alenljung

Messages: 4
Registered: July 2009

Junior Member

How can I declare that for example a Set contains objects of some type
and then initialize it to be empty. Neither I or II below works, but III
does.

(I) Not OK
let a:Set(Integer)=Set{} in a

'Init expression type does not conform to type of variable (a).'

(II) Not OK
let a:Set(Integer)=Set(Integer){} in a

'1:20:1:31 "collectionTypeIdentifierCS" expected instead of "Set(Integer)"'

(III) OK
let a:Set(Integer)=Set{1,3,2} in a

2
1
3

Regards
Tord

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Re: How to declare type of empty collection in OCL? [message #61256 is a reply to message #61231]

Tue, 14 November 2006 11:21

Eclipse User

Originally posted by: merks.ca.ibm.com

Tord,

I'll forward your question to the new OCL newsgroup.

Tord Alenljung wrote:
> How can I declare that for example a Set contains objects of some type
> and then initialize it to be empty. Neither I or II below works, but
> III does.
>
> (I) Not OK
> let a:Set(Integer)=Set{} in a
>
> 'Init expression type does not conform to type of variable (a).'
>
> (II) Not OK
> let a:Set(Integer)=Set(Integer){} in a
>
> '1:20:1:31 "collectionTypeIdentifierCS" expected instead of
> "Set(Integer)"'
>
> (III) OK
> let a:Set(Integer)=Set{1,3,2} in a
>
> 2
> 1
> 3
>
> Regards
> Tord

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Re: How to declare type of empty collection in OCL? [message #61376 is a reply to message #61256]

Tue, 14 November 2006 14:12

Eclipse User

Originally posted by: cdamus.ca.ibm.com

Hi, Tord,

The element type of a collection literal is inferred from its contents (as
the common supertype of its elements, which may be OclAny or
Collection(OclAny) in mixed cases). The inferred element type of an empty
collection literal is OclVoid, which conforms to all other types, so your
expression (I) should work.

This is a bug. Would you mind raising it? (on the MDT UML2 OCL component):

https://bugs.eclipse.org/bugs/enter_bug.cgi?product=MDT& version=1.0.1&component=UML2%20OCL&bug_severity=norm al&form_name=enter_bug

Thanks,

Christian

Ed Merks wrote:

> Tord,
>
> I'll forward your question to the new OCL newsgroup.
>
>
> Tord Alenljung wrote:
>> How can I declare that for example a Set contains objects of some type
>> and then initialize it to be empty. Neither I or II below works, but
>> III does.
>>
>> (I) Not OK
>> let a:Set(Integer)=Set{} in a
>>
>> 'Init expression type does not conform to type of variable (a).'
>>
>> (II) Not OK
>> let a:Set(Integer)=Set(Integer){} in a
>>
>> '1:20:1:31 "collectionTypeIdentifierCS" expected instead of
>> "Set(Integer)"'
>>
>> (III) OK
>> let a:Set(Integer)=Set{1,3,2} in a
>>
>> 2
>> 1
>> 3
>>
>> Regards
>> Tord

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Re: How to declare type of empty collection in OCL? [message #61449 is a reply to message #61376]

Wed, 15 November 2006 12:11

Tord Alenljung

Messages: 4
Registered: July 2009

Junior Member

Bug report at https://bugs.eclipse.org/bugs/show_bug.cgi?id=164614

Thanks
Tord

Christian W. Damus wrote:
> Hi, Tord,
>
> The element type of a collection literal is inferred from its contents (as
> the common supertype of its elements, which may be OclAny or
> Collection(OclAny) in mixed cases). The inferred element type of an empty
> collection literal is OclVoid, which conforms to all other types, so your
> expression (I) should work.
>
> This is a bug. Would you mind raising it? (on the MDT UML2 OCL component):
>
> https://bugs.eclipse.org/bugs/enter_bug.cgi?product=MDT& version=1.0.1&component=UML2%20OCL&bug_severity=norm al&form_name=enter_bug
>
> Thanks,
>
> Christian
>
>
> Ed Merks wrote:
>
>> Tord,
>>
>> I'll forward your question to the new OCL newsgroup.
>>
>>
>> Tord Alenljung wrote:
>>> How can I declare that for example a Set contains objects of some type
>>> and then initialize it to be empty. Neither I or II below works, but
>>> III does.
>>>
>>> (I) Not OK
>>> let a:Set(Integer)=Set{} in a
>>>
>>> 'Init expression type does not conform to type of variable (a).'
>>>
>>> (II) Not OK
>>> let a:Set(Integer)=Set(Integer){} in a
>>>
>>> '1:20:1:31 "collectionTypeIdentifierCS" expected instead of
>>> "Set(Integer)"'
>>>
>>> (III) OK
>>> let a:Set(Integer)=Set{1,3,2} in a
>>>
>>> 2
>>> 1
>>> 3
>>>
>>> Regards
>>> Tord
>

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Re: How to declare type of empty collection in OCL? [message #595597 is a reply to message #61231]

Tue, 14 November 2006 11:21

Ed Merks

Messages: 33142
Registered: July 2009

Senior Member

Tord,

I'll forward your question to the new OCL newsgroup.

Tord Alenljung wrote:
> How can I declare that for example a Set contains objects of some type
> and then initialize it to be empty. Neither I or II below works, but
> III does.
>
> (I) Not OK
> let a:Set(Integer)=Set{} in a
>
> 'Init expression type does not conform to type of variable (a).'
>
> (II) Not OK
> let a:Set(Integer)=Set(Integer){} in a
>
> '1:20:1:31 "collectionTypeIdentifierCS" expected instead of
> "Set(Integer)"'
>
> (III) OK
> let a:Set(Integer)=Set{1,3,2} in a
>
> 2
> 1
> 3
>
> Regards
> Tord

Ed Merks
Professional Support: https://www.macromodeling.com/

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