My opinion: for scripting ok, for the general language not yet convinced. `notNil and: []` + `isNil or: []` are only slightly longer and somehow easier to read for me. Remain the block arguments; I also find myself avoiding temporaries sometimes, but Levente is right that they are the idiomatic way to to this, not in:-like constructs: (xyz := ...) notNil and: [xyz ...]
Maybe one should rather refactor the candidate senders to use less nils? Or guard against nil at the top if possible?
Have you had a look at Java 8's Optional class? Nil can receive messages in Smalltalk, which Java null can't. Is nil therefore a good empty Optional or should these concepts be separate?
Thiede, Christoph Christoph.Thiede@student.hpi.uni-potsdam.de schrieb am Mo., 16. März 2020, 19:58:
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@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@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@source.squeak.org < commits@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!