[Cuis-dev] Methods that return multiple values

rabbit rabbit at callistohouse.org
Sat Jun 24 18:05:52 PDT 2023 

Oh! That’s exactly the semantics I’m expecting! When the method resumes I’m absolutely expecting self to be the new guy. If a subsequent message call is not understood, a DNU would be raised. Can we get a parallel method to give me those semantics, please? Portability is #becomeForward: but not that breaks your existing contract. Could we test #isEventual in #becomeForward:, perhaps?

❤️‍🔥🐰

On Sat, Jun 24, 2023 at 20:38, Juan Vuletich <[juan at cuis.st](mailto:On Sat, Jun 24, 2023 at 20:38, Juan Vuletich <<a href=)> wrote:

> I'm not familiar with your code.
>
> But that error message you get is real. It is not a problem in Cuis. It is a problem in your code. You are doing #becomeForward: of an object that is in the midst of running a method. If the become is done, that method will later resume running, but self will be a different object, maybe an object of another class, where this method is not defined, and can not be run.
>
> I suggest understanding this problem. It is safer to only do become on objects that are NOT running any methods at that moment.
>
> Squeak doesn't give you this error simply because Squeak doesn't check for this problem. A VM crash is likely in this situation. I actually added this check to Cuis after someone (it was a long time ago, I don't remember who it was) was experiencing VM crashes because a method was resumed on a becomed object, and was writing instance variables that didn't exist in the becomed object.
>
> HTH,
>
> On 6/24/2023 10:57 AM, rabbit via Cuis-dev wrote:
>
>> Hi Juan, I'm attaching 2 squeak source files, one with 2 methods in compatibility and the other the source.st out of my latest PromisesLocal-rabbt.66,mcz.
>>
>> I got the Vat's eventual process working (issues with terminate),
>>
>> but I'm blowing up on a call to #becomeForward:, from ENearPromise>>#becomeContext:, when resolving a promise. Here is an image of the resulting debugger. Is there more information I could provide or is someone willing to attempt to reproduce? Many thanks! ❤️‍🔥🐰
>>
>> On 6/23/23 20:50, rabbit via Cuis-dev wrote:
>>
>>> Ahh! Thanks for the reminder. That’s how I started loading code a month ago or whenever I was loading mczs. I’ll look into it tomorrow.
>>>
>>> Is it possible to get Monticello pkg loading working again? That’d be very good.
>>>
>>> What’s my go to solution for code packaging in Cuis? I’d like to establish Crypto in Cuis.
>>>
>>> ❤️‍🔥🐰
>>>
>>> On Fri, Jun 23, 2023 at 19:21, Juan Vuletich via Cuis-dev <[cuis-dev at lists.cuis.st](mailto:On%20Fri,%20Jun%2023,%202023%20at%2019:21,%20Juan%0A%20%20%20%20%20%20%20%20Vuletich%20via%20Cuis-dev%20%3C%3Ca%20href=)> wrote:
>>>
>>>> Hi rabbit,
>>>>
>>>> I suggest unzipping the Monticello files to extract the code in plain text (yes, Monticello files are just zip files). When you are there, you can also fix the line ending convention of the files. And of course, you'd neet to check the code, because Cuis is not 100% compatible with Squeak.
>>>>
>>>> We don't use Monticello in Cuis. At some point in the past it was possible to open MC files in Cuis, but nobody used that feature in ages and it got bitrotten.
>>>>
>>>> Thanks,
>>>>
>>>> On 6/23/2023 4:00 PM, rabbit via Cuis-dev wrote:
>>>>
>>>>> 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
>>>>>
>>>>> --
>>>>> ❤️‍🔥🐰
>>>>
>>>> --
>>>> Juan Vuletich
>>>> cuis.st
>>>> github.com/jvuletich
>>>> researchgate.net/profile/Juan-Vuletich
>>>> independent.academia.edu/JuanVuletich
>>>> patents.justia.com/inventor/juan-manuel-vuletich
>>>> linkedin.com/in/juan-vuletich-75611b3
>>>> twitter.com/JuanVuletich
>>
>> --
>> ❤️‍🔥🐰
>
> --
> Juan Vuletich
> cuis.st
> github.com/jvuletich
> researchgate.net/profile/Juan-Vuletich
> independent.academia.edu/JuanVuletich
> patents.justia.com/inventor/juan-manuel-vuletich
> linkedin.com/in/juan-vuletich-75611b3
> twitter.com/JuanVuletich
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