I think I saw a coding pattern a while ago that allows you to do the following: cond1 , cond2 , cond3 , cond4 And providing a kind of folding selector condition #and: you would get: [ cond1 and: [ cond2 and: [ cond3 and: [ cond4 ] ] ] ]. for example: conditions := [ : each | each firstName = 'Boca' ] , [ : each | each lastName = 'Baret' ] , [ : each | each fullName = 'Virgasia' ]. such that the following assert is met: self assert: conditions equals: [ : each | each firstName = 'Boca' and: [ each lastName = 'Baret' and: [ each fullName = 'Virgasia' ] ] ]. Any ideas or pointers? Cheers, Hernán
Not satisfying the equality, but you can use polymorphism. Block >> , aBlock ^ BlockCompositor andAll: OrderedCollection with: self with: aBlock BlockCompositor >> #, aBlock conditions add: aBlock. BlockCompositor >> value: anObject ^ conditions allSatisfy: [:e | e value: anObject ] I don't really like the name BlockCompositor, but can't think of a better name at the moment. You could also implement logic for #or: using #+ and: #anySatisfy: for example, but need to safeguard against mixing both conditions. On Mon, 14 Mar 2022 at 22:29, Hernán Morales Durand < hernan.morales@gmail.com> wrote:
I think I saw a coding pattern a while ago that allows you to do the following:
cond1 , cond2 , cond3 , cond4
And providing a kind of folding selector condition #and: you would get:
[ cond1 and: [ cond2 and: [ cond3 and: [ cond4 ] ] ] ].
for example:
conditions := [ : each | each firstName = 'Boca' ] , [ : each | each lastName = 'Baret' ] , [ : each | each fullName = 'Virgasia' ].
such that the following assert is met:
self assert: conditions equals: [ : each | each firstName = 'Boca' and: [ each lastName = 'Baret' and: [ each fullName = 'Virgasia' ] ] ].
Any ideas or pointers?
Cheers,
Hernán
This is an interesting pattern. Thank you for sharing. Hernán El mar, 15 mar 2022 a las 4:43, Julián Maestri (<serpi90@gmail.com>) escribió:
Not satisfying the equality, but you can use polymorphism.
Block >> , aBlock ^ BlockCompositor andAll: OrderedCollection with: self with: aBlock
BlockCompositor >> #, aBlock conditions add: aBlock.
BlockCompositor >> value: anObject ^ conditions allSatisfy: [:e | e value: anObject ]
I don't really like the name BlockCompositor, but can't think of a better name at the moment.
You could also implement logic for #or: using #+ and: #anySatisfy: for example, but need to safeguard against mixing both conditions.
On Mon, 14 Mar 2022 at 22:29, Hernán Morales Durand < hernan.morales@gmail.com> wrote:
I think I saw a coding pattern a while ago that allows you to do the following:
cond1 , cond2 , cond3 , cond4
And providing a kind of folding selector condition #and: you would get:
[ cond1 and: [ cond2 and: [ cond3 and: [ cond4 ] ] ] ].
for example:
conditions := [ : each | each firstName = 'Boca' ] , [ : each | each lastName = 'Baret' ] , [ : each | each fullName = 'Virgasia' ].
such that the following assert is met:
self assert: conditions equals: [ : each | each firstName = 'Boca' and: [ each lastName = 'Baret' and: [ each fullName = 'Virgasia' ] ] ].
Any ideas or pointers?
Cheers,
Hernán
Pattern? I'd call it an antipattern myself. Note that we can already construct { block1 . block2 . block3 } and write { block1 . block2 . block3 } allSatisfy: [:each | each value]. so we don't have to abuse the #, selector or write a single new method to get the "flattened" structure you're after. Collection methods for: 'collections of blocks' allSatisfied ^self allSatisfy: [:each | each value] anySatisfied ^self anySatisfy: [:each | each value] noneSatisfied ^self noneSatisfy: [:each | each value] if you do feel like adding a few methods, whereupon { block1 . block2 . block3 } allSatisfied Didn't VW recently implement {} syntax natively? Or was that VAST? In all seriousness, when is it better to use ComplexCondition than to rewrite? On Wed, 16 Mar 2022 at 14:38, Hernán Morales Durand < hernan.morales@gmail.com> wrote:
This is an interesting pattern. Thank you for sharing.
Hernán
El mar, 15 mar 2022 a las 4:43, Julián Maestri (<serpi90@gmail.com>) escribió:
Not satisfying the equality, but you can use polymorphism.
Block >> , aBlock ^ BlockCompositor andAll: OrderedCollection with: self with: aBlock
BlockCompositor >> #, aBlock conditions add: aBlock.
BlockCompositor >> value: anObject ^ conditions allSatisfy: [:e | e value: anObject ]
I don't really like the name BlockCompositor, but can't think of a better name at the moment.
You could also implement logic for #or: using #+ and: #anySatisfy: for example, but need to safeguard against mixing both conditions.
On Mon, 14 Mar 2022 at 22:29, Hernán Morales Durand < hernan.morales@gmail.com> wrote:
I think I saw a coding pattern a while ago that allows you to do the following:
cond1 , cond2 , cond3 , cond4
And providing a kind of folding selector condition #and: you would get:
[ cond1 and: [ cond2 and: [ cond3 and: [ cond4 ] ] ] ].
for example:
conditions := [ : each | each firstName = 'Boca' ] , [ : each | each lastName = 'Baret' ] , [ : each | each fullName = 'Virgasia' ].
such that the following assert is met:
self assert: conditions equals: [ : each | each firstName = 'Boca' and: [ each lastName = 'Baret' and: [ each fullName = 'Virgasia' ] ] ].
Any ideas or pointers?
Cheers,
Hernán
ComplexCondition as described in [Andres Valloud, "A Mentoring Course on Smalltalk"](http://www.lulu.com/product/paperback/a-mentoring-course-on-smalltalk/378889...) is available at http://www.squeaksource.com/ComplexCondition.html With it, you can do something like: ``` ^[a includes: $.], [b includes: $.] ifAllTrue: [a < b] ifAnyTrue: [b includes: $.] otherwise: [a > b] ```
Exactly. This was what I was looking for. Thank you Sean. Hernán El mar, 15 mar 2022 a las 19:15, <sean@clipperadams.com> escribió:
ComplexCondition as described in Andres Valloud, "A Mentoring Course on Smalltalk" <http://www.lulu.com/product/paperback/a-mentoring-course-on-smalltalk/378889...> is available at http://www.squeaksource.com/ComplexCondition.html
With it, you can do something like:
^[a includes: $.], [b includes: $.] ifAllTrue: [a < b] ifAnyTrue: [b includes: $.] otherwise: [a > b]
The motivating example can be written aHasDot := a includes: $.. bHasDot := b includes: $.. ^aHasDot = bHasDot ifFalse: [bHasDot] ifTrue: [aHasDot ifTrue: [a < b] ifFalse: [a > b]] (Dijkstra was right. People *do* forget that '=' is one of the standard Boolean operations, and it matters.) This is absolutely straightforward, and without wasting any time wondering what the three-headed IF monster is, we can go straight to the big puzzle: "I can see at a glance what this DOES, but what the heck does it MEAN?" When would this be useful? What would be a good name for this combination, however expressed? I think the moral here is "when you have code whose structure is so complex that you are tempted to construct special control flow objects to make it LOOK simpler, rewrite it so that it IS simpler." I once wrote a class called Distributor based on Boost 'signal's. It was an interesting exercise, and I am still finding mistakes in it. It was not entirely unlike ComplexCondition. What I *haven't* done in the 10 years since I wrote it is found any use for it. On Wed, 16 Mar 2022 at 07:15, <sean@clipperadams.com> wrote:
ComplexCondition as described in Andres Valloud, "A Mentoring Course on Smalltalk" <http://www.lulu.com/product/paperback/a-mentoring-course-on-smalltalk/378889...> is available at http://www.squeaksource.com/ComplexCondition.html
With it, you can do something like:
^[a includes: $.], [b includes: $.] ifAllTrue: [a < b] ifAnyTrue: [b includes: $.] otherwise: [a > b]
participants (4)
-
Hernán Morales Durand -
Julián Maestri -
Richard O'Keefe -
sean＠clipperadams.com