Hi Christoph,

They are okay for scripts, but we know that methods like that always end 
up being used out of scripts, and are even misused every now and then.
They are especially susceptible to misuse when their return value is 
ignored; in which case they are both equivalent to #ifNotNil:.

I'm also not sure whether these methods belong to ProtoObject or not.
I know the other nil handling methods are there as well, but that doesn't 
mean all such methods belong there.
E.g. #ifNil:/#ifNotNil: should be there because the current compiler and 
VM will make those available for all objects provided the methods are 
inlined. But #isNil and #notNil have no such properties, so they belong 
more to Object than ProtoObject in my opinion.


Levente

On Mon, 16 Mar 2020, Thiede, Christoph wrote:

> 
> Hi all,
> 
> 
> after the release has been managed successfully, I would like to kindly push this proposal. In the latest months, I found myself to really often desiring #isNilOr: or #notNilAnd:. How would you think about these convenience
> selectors? :-)
> 
> 
> Best,
> 
> Christoph
> 
> _________________________________________________________________________________________________________________________________________________________________________________________________________________________________
> Von: Thiede, Christoph
> Gesendet: Mittwoch, 11. Dezember 2019 11:01:44
> An: Squeak Dev
> Betreff: #isNilOr:, #notNilAnd:  
> 
> Hi all, just another idea for a hypothetic extension to ProtoObject:
> 
> 
> ProtoObject >> #isNilOr: aBlock
> 
> ^ aBlock cull: self
> 
> UndefinedObject >> #isNilOr: aBlock
> 
> ^ true
> 
> ProtoObject >> #notNilAnd: aBlock
> 
> ^ aBlock cull: self
> 
> UndefinedObject >> #notNilAnd: aBlock
> 
> ^ false
> 
> 
> Examples:
> 
> parentObject notNilAnd: #canBrowseSubtopic.
> 
> helpClass notNilAnd: [:hC| hC usesCodeStyling].
> 
> self selectionIndex isNilOr: [:index | index > 2].
> 
> anObject isNilOr: #isZero.
> 
> foo isNilOr: #isNotEmpty.
> 
> 
> Just a bit syntactic sugar for idiomatic problems such as below. In particular, I found several possible applications for #notNilAnd: in my image.
> 
> 
> Go ahead and tell me why it would be a bad idea :)
> 
> 
> Best,
> 
> Christoph
> 
> 
> _________________________________________________________________________________________________________________________________________________________________________________________________________________________________
> Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von Thiede, Christoph
> Gesendet: Freitag, 25. Oktober 2019 19:21 Uhr
> An: gettimothy via Squeak-dev
> Betreff: Re: [squeak-dev] The Inbox: HelpSystem-Core-ct.123.mcz  
> 
> If you're needing a decision, I'd vote for option 3.
> 
> _________________________________________________________________________________________________________________________________________________________________________________________________________________________________
> Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von Taeumel, Marcel
> Gesendet: Mittwoch, 16. Oktober 2019 11:14:15
> An: gettimothy via Squeak-dev
> Betreff: Re: [squeak-dev] The Inbox: HelpSystem-Core-ct.123.mcz  
> Quick suggestion on the formatting. This one:
> ^ self canBrowseTopic or: [
>    parentTopic ifNotNil: #canBrowseSubtopic ifNil: [false]]
> 
> could become:
> 
> ^ self canBrowseTopic or: [
>    parentTopic
>    ifNil: [false]
>    ifNotNil: [:topic | topic canBrowseSubtopic]]
> 
> or:
> 
> ^ self canBrowseTopic
>       or: [parentTopic notNil and: [parentTopic canBrowseSubtopic]]
> 
> Hmmm... what are other opinions on this? There is no need for #ifNil/ifNotNil in such a boolean expression?
> 
> Best,
> Marcel
> 
>
>       Am 13.10.2019 21:04:19 schrieb commits at source.squeak.org <commits at source.squeak.org>:
>
>       A new version of HelpSystem-Core was added to project The Inbox:
>       http://source.squeak.org/inbox/HelpSystem-Core-ct.123.mcz
>
>       ==================== Summary ====================
>
>       Name: HelpSystem-Core-ct.123
>       Author: ct
>       Time: 13 October 2019, 9:04:08.373932 pm
>       UUID: dec7ceca-320f-d945-8d2a-c2f6a5e49a52
>       Ancestors: HelpSystem-Core-ct.120
>
>       Refactors HelpBrowser menu: Move menu stuff from HelpBrowser into HelpTopic hierarchy in favor of a better object design
>
>       Thanks again, Marcel :-)
>
>       =============== Diff against HelpSystem-Core-ct.120 ===============
>
>       Item was added:
>       + ----- Method: AbstractHelpTopic>>browseTopicFromParent: (in category 'tools') -----
>       + browseTopicFromParent: parentTopic
>       +
>       + self canBrowseTopic
>       + ifTrue: [^ self browseTopic].
>       + parentTopic canBrowseSubtopic
>       + ifTrue: [^ parentTopic browseSubtopic: self].
>       + !
>
>       Item was added:
>       + ----- Method: AbstractHelpTopic>>canBrowseSubtopic (in category 'testing') -----
>       + canBrowseSubtopic
>       +
>       + ^ false!
>
>       Item was added:
>       + ----- Method: AbstractHelpTopic>>canBrowseTopic (in category 'testing') -----
>       + canBrowseTopic
>       +
>       + ^ false!
>
>       Item was added:
>       + ----- Method: AbstractHelpTopic>>canBrowseTopicFromParent: (in category 'testing') -----
>       + canBrowseTopicFromParent: parentTopic
>       +
>       + ^ self canBrowseTopic or: [
>       + parentTopic ifNotNil: #canBrowseSubtopic ifNil: [false]]!
>
>       Item was added:
>       + ----- Method: AbstractHelpTopic>>topicMenu:parentTopic: (in category 'menus') -----
>       + topicMenu: aMenu parentTopic: parentTopic
>       +
>       + aMenu
>       + add: 'Inspect (i)' translated target: self action: #inspect;
>       + add: 'Explore (I)' translated target: self action: #explore.
>       + (self canBrowseTopicFromParent: parentTopic)
>       + ifTrue: [
>       + aMenu add: 'Browse (b)' translated
>       + target: self
>       + selector: #browseTopicFromParent:
>       + argumentList: {parentTopic} ].
>       +
>       + ^ aMenu!
>
>       Item was added:
>       + ----- Method: AbstractHelpTopic>>topicMenuKey:fromParent: (in category 'menus') -----
>       + topicMenuKey: aChar fromParent: parentTopic
>       +
>       + aChar
>       + caseOf: {
>       + [$b] -> [(self canBrowseTopicFromParent: parentTopic)
>       + ifTrue: [ self browseTopicFromParent: parentTopic ]].
>       + [$i] -> [self inspect].
>       + [$I] -> [self explore] }
>       + otherwise: [^ false].
>       + ^ true!
>
>       Item was added:
>       + ----- Method: ClassAPIHelpTopic>>canBrowseTopic (in category 'testing') -----
>       + canBrowseTopic
>       +
>       + ^ true!
>
>       Item was added:
>       + ----- Method: ClassBasedHelpTopic>>canBrowseSubtopic (in category 'testing') -----
>       + canBrowseSubtopic
>       +
>       + ^ true!
>
>       Item was added:
>       + ----- Method: ClassBasedHelpTopic>>canBrowseTopic (in category 'testing') -----
>       + canBrowseTopic
>       +
>       + ^ true!
>
>       Item was added:
>       + ----- Method: DirectoryBasedHelpTopic>>canBrowseTopic (in category 'testing') -----
>       + canBrowseTopic
>       +
>       + ^ true!
>
>       Item was added:
>       + ----- Method: FileBasedHelpTopic>>canBrowseTopic (in category 'testing') -----
>       + canBrowseTopic
>       +
>       + ^ true!
>
>       Item was removed:
>       - ----- Method: HelpBrowser>>browseTopic (in category 'actions') -----
>       - browseTopic
>       -
>       - ^ (self currentTopic respondsTo: #browseTopic)
>       - ifTrue: [self currentTopic browseTopic]
>       - ifFalse: [self currentParentTopic browseSubtopic: self currentTopic]!
>
>       Item was removed:
>       - ----- Method: HelpBrowser>>canBrowseTopic (in category 'testing') -----
>       - canBrowseTopic
>       -
>       - ^ (self currentTopic respondsTo: #browseTopic)
>       - or: [self currentParentTopic respondsTo: #browseSubtopic:]!
>
>       Item was removed:
>       - ----- Method: HelpBrowser>>exploreTopic (in category 'actions') -----
>       - exploreTopic
>       -
>       - ^ self currentTopic explore!
>
>       Item was removed:
>       - ----- Method: HelpBrowser>>inspectTopic (in category 'actions') -----
>       - inspectTopic
>       -
>       - ^ self currentTopic inspect!
>
>       Item was changed:
>       ----- Method: HelpBrowser>>treeKey:from:event: (in category 'menus') -----
>       treeKey: aChar from: aView event: anEvent
>
>       anEvent anyModifierKeyPressed ifFalse: [^ false].
>       + ^ (self currentTopic topicMenuKey: aChar fromParent: self currentParentTopic)!
>       - aChar
>       - caseOf: {
>       - [$b] -> [self browseTopic].
>       - [$i] -> [self inspectTopic].
>       - [$I] -> [self exploreTopic]. }
>       - otherwise: [^ false].
>       - ^ true!
>
>       Item was changed:
>       ----- Method: HelpBrowser>>treeListMenu: (in category 'menus') -----
>       treeListMenu: aMenu
> 
>
>       + ^ self currentTopic
>       + ifNil: [aMenu]
>       + ifNotNil: [:topic | topic
>       + topicMenu: aMenu
>       + parentTopic: self currentParentTopic]!
>       - self currentTopic ifNil: [^ aMenu].
>       -
>       - aMenu
>       - add: 'Inspect (i)' action: #inspectTopic;
>       - add: 'Explore (I)' action: #exploreTopic.
>       -
>       - self canBrowseTopic ifTrue: [
>       - aMenu
>       - addLine;
>       - add: 'Browse (b)' action: #browseTopic].
>       -
>       - ^ aMenu!
>
>       Item was added:
>       + ----- Method: MethodListHelpTopic>>canBrowseTopic (in category 'testing') -----
>       + canBrowseTopic
>       +
>       + ^ true!
>
>       Item was added:
>       + ----- Method: PackageAPIHelpTopic>>canBrowseTopic (in category 'testing') -----
>       + canBrowseTopic
>       +
>       + ^ true!
> 
> 
> 
>