[Cuis-dev] Methods that return multiple values

[rabbit]

I just realized I have been working in squeak. I updated PromisesLocal-rabbt.66.mcz and am attaching it. I am getting the error below when I 'browse code' or 'install Mionticello package'. I do not know. How can I load Monticello packages? Any way to get the Installer available in cuis? Install Monticello config maps?

I appreciate you,
rabbit

On 6/22/23 16:21, rabbit via Cuis-dev wrote:

> Hey! I got inspired by your proposal, Luciano, and here's my solution in eventual promises. Code can be loaded as:
>
>> Installer ss project: 'Cryptography'; install: 'ProCrypto.release.3'.
>
> I added a test method
>
>> RefsTest>>#testMultiReturns
>>
>> | selectCount unionFlag pair |
>> unionFlag := false.
>> selectCount := 0.
>> ((pair := self promiseResolverPair) key xgcd: 9)
>> <<* [:each | selectCount := selectCount + 1. Transcript cr; show: 'each = ', each];
>> <<* [:g :s :t | unionFlag := true. Transcript cr; show: 'g = ', g, '; s = ', s, '; t = ', t. g + s + t].
>> pair value resolve: 21.
>> (Delay forMilliseconds: 333) wait.
>> self assert: (selectCount == 3).
>> self assert: (unionFlag).
>
> This calls new multireturn #xgcd: method
>
>> xgcd: anInteger
>> " 21 xgcd: 9"
>> | g s t |
>> g := self gcd: anInteger.
>> s := self / g.
>> t := anInteger / g.
>> ^ { g. s. t}
>
> And in the test method there are eventual sends (#<<*) to the promise of the #xgcd: send once the reciever promise is resolved to 21. This implementation detects cardinality of the continuation block and sends #whenResolved: appropriately, for future evaluation.
>
>> Object>>#<<* continuation
>>
>> (continuation numArgs == 1)
>> ifTrue: [^ self whenResolved: [:result | result do: [:each | continuation value: each]]].
>> ^ self whenResolved: [:result | continuation valueWithArguments: result].
>
> One can see a 1 cardinality schedules the continuation to evaluate with each result, while a continuation with cardinality 2 or more will be scheduled to receive all results. #valueWithArguments:
>
> Here are 2 return handlers,
>
>> promise := ((pair := self promiseResolverPair) key xgcd: 9).
>
> the first for each argument
>
>> promise <<* [:each | selectCount := selectCount + 1. Transcript cr; show: 'each = ', each];
>
> and the second for all three arguments.
>
>> promise <<* [:g :s :t | unionFlag := true. Transcript cr; show: 'g = ', g, '; s = ', s, '; t = ', t. g + s + t].
>
> --
> ❤️‍🔥🐰
>
> On 6/21/23 09:44, Luciano Notarfrancesco via Cuis-dev wrote:
>
>> Interesting, thanks for sharing!
>> Actually I think it’s the same thing I did, my implementation calls BlockClosure>>#valueWithPossibleArgs: and takes only as many arguments as needed by the block but the array can be bigger than that (it should be named #valueWithPossibleArguments: tho, abbreviations are ugly).
>>
>> On Wed, 21 Jun 2023 at 15:37 Christian Haider via Cuis-dev <cuis-dev at lists.cuis.st> wrote:
>>
>>> I added something similar to my Values package (VW and ports).
>>>
>>> The source is
>>>
>>> SequenceableCollection>>asArgumentsIn: aBlock
>>>
>>> "Evaluate aBlock with the receiver's elements as parameters.
>>>
>>> aBlock takes its arguments from the receiver.
>>>
>>> 'ok'
>>>
>>> #(1 2 3) asArgumentsIn: [:a :b :c | a + b + c]
>>>
>>> #(1 2 3) asArgumentsIn: [:a :b | a + b]
>>>
>>> #(1 2 3) asArgumentsIn: [:a | a]
>>>
>>> #(1 2 3) asArgumentsIn: [42]
>>>
>>> 'not ok'
>>>
>>> #(1 2 3) asArgumentsIn: [:a :b :c :d | a + b + c + d]
>>>
>>> "
>>>
>>> ^aBlock cullWithArguments: self asArray
>>>
>>> The difference is that it takes a list of any size and picks out the first items and binds them to the variables.
>>>
>>> I use it often for CSV processing like
>>>
>>> (line tokensBasedOn: $;) asArgumentsIn: [:first :second :y | … ].
>>>
>>> I am just a bit unhappy with the name – it is too long. It reads ok though.
>>>
>>> The pipe character is an interesting idea. I have to think about it.
>>>
>>> I am use it for a while now and I am very happy with it.
>>>
>>> Happy hacking,
>>>
>>> Christian
>>>
>>> Von: Cuis-dev <cuis-dev-bounces at lists.cuis.st> Im Auftrag von Luciano Notarfrancesco via Cuis-dev
>>> Gesendet: Mittwoch, 21. Juni 2023 15:13
>>> An: Discussion of Cuis Smalltalk <cuis-dev at lists.cuis.st>
>>> Cc: Luciano Notarfrancesco <luchiano at gmail.com>
>>> Betreff: [Cuis-dev] Methods that return multiple values
>>>
>>> Smalltalk doesn’t have a convention for methods returning multiple values, and I’m not aware of any implementation.
>>>
>>> An example of such thing is the extended gcd: ‘a xgcd: b’ returns g, s, t where g is the gcd, and as + bt = g. Writing methods that return multiple values is easy with the curly brackets syntax, Integer>>#xgcd: ends with something like
>>>
>>> ^ {g. s. t}
>>>
>>> But using sending messages that return multiple values is kind of annoying, I end up doing something like:
>>>
>>> xgcd := a xgcd: b.
>>>
>>> g := xgcd at: 1.
>>>
>>> s := xgcd at: 2.
>>>
>>> t := xgcd at: 3
>>>
>>> Some years ago I thought about using blocks for this, but I never tried it. Today I just did a little experiment implementing anArray | aBlock as ‘^ aBlock valueWithPossibleArgs: self’ and I can do:
>>>
>>> (a xgcd: b) | [:g :s :t| … ]
>>>
>>> This is seems quite nice already, I guess I’ll start using it and see how it feels. But the point of this mail is not to show a solution, but to ask if anyone have thought about this or if they know any nicer solutions. Any ideas?
>>>
>>> --
>>> Cuis-dev mailing list
>>> Cuis-dev at lists.cuis.st
>>> https://lists.cuis.st/mailman/listinfo/cuis-dev

--
❤️‍🔥🐰
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