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Bug 354401

Summary:	Xtend2 - add a union function
Product:	[Modeling] TMF	Reporter:	Bernd Kolb <b.kolb>
Component:	Xtext	Assignee:	Project Inbox <tmf.xtext-inbox>
Status:	CLOSED FIXED	QA Contact:
Severity:	enhancement
Priority:	P3	CC:	christian.dietrich.opensource, sebastian.zarnekow, sven.efftinge
Version:	unspecified
Target Milestone:	---
Hardware:	PC
OS:	Mac OS X - Carbon (unsup.)
Whiteboard:

Description Bernd Kolb

2011-08-10 11:45:21 EDT

Build Identifier: 

Please add a union function which creates a collection list out of two given collections

Reproducible: Always

Comment 1 Sebastian Zarnekow

2011-08-10 11:58:35 EDT

Why doesn't listA + listB work for you? If you want a union, you could even do a newLinkedHashSet(listA + listB). Please reopen if I missed your point.

Comment 2 Sebastian Zarnekow

2011-08-10 11:59:36 EDT

Sorry, I meant (listA + listB).toSet

Comment 3 Bernd Kolb

2011-08-10 12:15:02 EDT

That works. But if you are somewhere in an expression it feels more natural (to me) to write
a.b.c.union(x.y.z).doSomething 

than

(a.b.c + x.y.z).doSomething

Please close again if you don't agree

Comment 4 Christian Dietrich

2011-08-11 14:54:27 EDT

what about

import static extension com.google.common.collect.Iterables.*

newArrayList("A","B").concat(newArrayList("C", "D"))

Comment 5 Sebastian Zarnekow

2011-08-11 15:02:55 EDT

I don't like the idea to have something like union on iterables or collections. Union (and intersection) are set operations and are indeed available on com.google.common.collect.Sets.

I can imagine to have #concat as an alias to iterable+iterable and #union, #intersection and #difference available on instances of java.util.Set

Comment 6 Sven Efftinge

2011-11-21 06:47:31 EST

Closing this since the standard lib supports (listA + listB).toSet and if that is not good enough in a certain context one can define an extension method for that context.

Comment 7 Karsten Thoms

2017-09-19 17:54:47 EDT

Closing all bugs that were set to RESOLVED before Neon.0

Comment 8 Karsten Thoms

2017-09-19 18:05:44 EDT

Closing all bugs that were set to RESOLVED before Neon.0