[Newbies] Re: How to empty a collection?
On Tue, 19 Feb 2008 16:06:50 +0100, cdrick wrote: ... I forgot that in my first attemp (and I knew that !)... col := #(1 2 3) asOrderedCollection. col removeAll: col. ^col returns an OrderedCollection(2) col removeAll: col copy is ok. So, following Bert suggestion, would it be possible to change removeAll: from... removeAll: aCollection aCollection do: [:each | self remove: each]. ^ aCollection to removeAll: aCollection aCollection copy do: [:each | self remove: each]. ^ aCollection or removeAll: aCollection aCollection == self ifTrue: [aCollection copy do: [:each | self remove: each]] ifFalse: [aCollection do: [:each | self remove: each]]. ^ aCollection or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Thumbs down, I do not want anybody copy a collection behind my back (however small or large it is) just because remove* has nothing to do with copy. Cédrick ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
cdrick a écrit : or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Cédrick aCollection == self is not the only case that can fail. Imagine i pass a wrapper collection on self, like a MappedCollection. When i will change self with remove:, i will also change the argument which is just a wrapper on self. Hope my explanations are not too much confusing... Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
On Tue, 19 Feb 2008 21:01:14 +0100, nicolas cellier wrote: cdrick a écrit : or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Cédrick aCollection == self is not the only case that can fail. Imagine i pass a wrapper collection on self, like a MappedCollection. When i will change self with remove:, i will also change the argument which is just a wrapper on self. Hope my explanations are not too much confusing... Let's see: Remove each element of aCollection from the receiver. If successful for each, answer aCollection. Otherwise create an error notification. What mapping would *not* raise the error notification ;-) BTW: MappedCollection does not exist in sq3.10-7159dev08.02.1.image ... /Klaus Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
Klaus D. Witzel a écrit : On Tue, 19 Feb 2008 21:01:14 +0100, nicolas cellier wrote: cdrick a écrit : or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Cédrick aCollection == self is not the only case that can fail. Imagine i pass a wrapper collection on self, like a MappedCollection. When i will change self with remove:, i will also change the argument which is just a wrapper on self. Hope my explanations are not too much confusing... Let's see: Remove each element of aCollection from the receiver. If successful for each, answer aCollection. Otherwise create an error notification. What mapping would *not* raise the error notification ;-) My interpretation of the comment was rather for the case when we try to remove an element which is not in the collection... But OK, I take it as is... However i can construct a test case that will not do what is expected and will not raise a notification, wanna bet? | collec1 collec2 | collec1 := OrderedCollection with: 'a' with: 'b' with: 'c'. collec2 := MappedCollection collection: collec1 map: (1 to: 2). collec2 only map first two elements 'a' and 'b' collec1 removeAll: collec2. this should remove 'a' and 'b' from collec1 self assert: collec1 first = 'c' too bad... it's 'b' BTW: MappedCollection does not exist in sq3.10-7159dev08.02.1.image ... MappedCollection is just an example of possible wrapper collection, even if there is none in core images nowadays, that's a classical pattern which avoid copying for example. MappedCOllection is in 3.9 image. /Klaus Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
On Tue, 19 Feb 2008 22:00:09 +0100, nicolas cellier wrote: Klaus D. Witzel a écrit : On Tue, 19 Feb 2008 21:01:14 +0100, nicolas cellier wrote: cdrick a écrit : or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Cédrick aCollection == self is not the only case that can fail. Imagine i pass a wrapper collection on self, like a MappedCollection. When i will change self with remove:, i will also change the argument which is just a wrapper on self. Hope my explanations are not too much confusing... Let's see: Remove each element of aCollection from the receiver. If successful for each, answer aCollection. Otherwise create an error notification. What mapping would *not* raise the error notification ;-) My interpretation of the comment was rather for the case when we try to remove an element which is not in the collection... But OK, I take it as is... However i can construct a test case that will not do what is expected and will not raise a notification, wanna bet? No, just let the next people who attempt to bring MappedCollection back to Squeak 3.10 take care ;-) BTW: do you have as much energy for fixing problems as you seem to have for imagine the currently non-existing ;-) This would help Squeak jump forward :) | collec1 collec2 | collec1 := OrderedCollection with: 'a' with: 'b' with: 'c'. collec2 := MappedCollection collection: collec1 map: (1 to: 2). collec2 only map first two elements 'a' and 'b' collec1 removeAll: collec2. this should remove 'a' and 'b' from collec1 self assert: collec1 first = 'c' too bad... it's 'b' BTW: MappedCollection does not exist in sq3.10-7159dev08.02.1.image ... MappedCollection is just an example of possible wrapper collection, even if there is none in core images nowadays, that's a classical pattern which avoid copying for example. MappedCOllection is in 3.9 image. /Klaus Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
Klaus D. Witzel a écrit : On Tue, 19 Feb 2008 22:00:09 +0100, nicolas cellier wrote: However i can construct a test case that will not do what is expected and will not raise a notification, wanna bet? No, just let the next people who attempt to bring MappedCollection back to Squeak 3.10 take care ;-) As a user of collection wrappers, proposed patch just hit the alarm buzzer my nervous brain is equipped with. But your position is wise. As long as a MappedCollection, lazy list or lazy collection (see these projects on SqueakSource) are all created under our control, we can manage... BTW: do you have as much energy for fixing problems as you seem to have for imagine the currently non-existing ;-) This would help Squeak jump forward :) That's precisely how i find and fix unknown bugs: Imagine how i could break current implementation. For this reason, most patches i proposed are minor. Hope a few are usefull, since adopted in 3.8.1, 3.9 and 3.10. Any minor contribution counts anyway :) Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
On Tue, 19 Feb 2008 02:35:34 +0100, Marcin Tustin wrote: Isn't Cedrick's aida solution going to be significantly faster? No, solutions based on #become: are the slowest possible. The VM has to sweep the whole memory, for all variables in the system, to find all references during #become:, like this | oop | oop := self someObject. [check+replace reference in variables of oop, then oop := oop nextObject. oop = 0 ] whileFalse. Now think that you (and every other user of your software ;-) have an .image with 2-4gigs every time you use #become: ... If you want something faster, look at Bert's myCollection removeAllSuchThat: [:each | true] and try to make it faster but keep still it correct (old elements must be nil'ed). /Klaus On Feb 19, 2008 1:02 AM, Ron Teitelbaum [EMAIL PROTECTED] wrote: Hi Sophie, aCollection copy do: [:anElement | aCollection remove: anElement ]. Why copy? If you start removing items from the collection, increasing the index will cause you to skip elements. Ron -Original Message- From: itsme213 I want to clear its contents (size goes back to zero), and can't seem to find something like #clear or #empty. Cannot use a new collection as there are shared references to it. Thanks - Sophie ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
