<html><head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> </head> <body> Hey! I got inspired by your proposal, Luciano, and here's my solution in eventual promises. Code can be loaded as: <blockquote> Installer ss project: 'Cryptography'; install: 'ProCrypto.release.3'. </blockquote> I added a test method <blockquote> 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). </blockquote> This calls new multireturn #xgcd: method <blockquote> xgcd: anInteger " 21 xgcd: 9" | g s t | g := self gcd: anInteger. s := self / g. t := anInteger / g. ^ { g. s. t} </blockquote> 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. <blockquote> Object>>#<<* continuation (continuation numArgs == 1) ifTrue: [^ self whenResolved: [:result | result do: [:each | continuation value: each]]]. ^ self whenResolved: [:result | continuation valueWithArguments: result]. </blockquote> 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, <blockquote> promise := ((pair := self promiseResolverPair) key xgcd: 9). </blockquote> the first for each argument <blockquote> promise <<* [:each | selectCount := selectCount + 1. Transcript cr; show: 'each = ', each]; </blockquote> and the second for all three arguments. <blockquote> promise <<* [:g :s :t | unionFlag := true. Transcript cr; show: 'g = ', g, '; s = ', s, '; t = ', t. g + s + t]. </blockquote> <pre class="moz-signature" cols="72">-- ❤️‍🔥🐰 </pre> <div class="moz-cite-prefix">On 6/21/23 09:44, Luciano Notarfrancesco via Cuis-dev wrote: </div> <blockquote type="cite" cite="mid:CAL5GDyrAapan9L5do9F_rM1oEkB_iE9=tfHu-i14ew25fHHH6A@mail.gmail.com"> <meta http-equiv="content-type" content="text/html; charset=UTF-8"/> <div dir="auto">Interesting, thanks for sharing!</div> <div dir="auto">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).</div> <div dir="auto"> </div> <div> <div class="gmail_quote"> <div dir="ltr" class="gmail_attr">On Wed, 21 Jun 2023 at 15:37 Christian Haider via Cuis-dev <<a href="mailto:cuis-dev@lists.cuis.st" moz-do-not-send="true" class="moz-txt-link-freetext">cuis-dev@lists.cuis.st</a>> wrote: </div> <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204,204,204)"> <div link="#0563C1" vlink="#954F72" style="overflow-wrap: break-word;" lang="DE"> <div class="m_-976565113171439616WordSection1"> 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 </div> </div> <div link="#0563C1" vlink="#954F72" style="overflow-wrap: break-word;" lang="DE"> <div class="m_-976565113171439616WordSection1"> <div style="border-width:1pt medium medium;border-style:solid none none;padding:3pt 0cm 0cm;border-color:rgb(225,225,225) currentcolor currentcolor"> Von: Cuis-dev <<a href="mailto:cuis-dev-bounces@lists.cuis.st" target="_blank" moz-do-not-send="true" class="moz-txt-link-freetext">cuis-dev-bounces@lists.cuis.st</a>> Im Auftrag von Luciano Notarfrancesco via Cuis-dev Gesendet: Mittwoch, 21. Juni 2023 15:13 An: Discussion of Cuis Smalltalk <<a href="mailto:cuis-dev@lists.cuis.st" target="_blank" moz-do-not-send="true" class="moz-txt-link-freetext">cuis-dev@lists.cuis.st</a>> Cc: Luciano Notarfrancesco <<a href="mailto:luchiano@gmail.com" target="_blank" moz-do-not-send="true" class="moz-txt-link-freetext">luchiano@gmail.com</a>> Betreff: [Cuis-dev] Methods that return multiple values </div> Smalltalk doesn’t have a convention for methods returning multiple values, and I’m not aware of any implementation. <div> 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 </div> <div> ^ {g. s. t} </div> <div> But using sending messages that return multiple values is kind of annoying, I end up doing something like: </div> <div> xgcd := a xgcd: b. </div> <div> g := xgcd at: 1. </div> <div> s := xgcd at: 2. </div> <div> t := xgcd at: 3 </div> <div> 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: </div> <div> (a xgcd: b) | [:g :s :t| … ] </div> <div> </div> <div> 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? </div> </div> </div> -- Cuis-dev mailing list <a href="mailto:Cuis-dev@lists.cuis.st" target="_blank" moz-do-not-send="true" class="moz-txt-link-freetext">Cuis-dev@lists.cuis.st</a> <a href="https://lists.cuis.st/mailman/listinfo/cuis-dev" rel="noreferrer" target="_blank" moz-do-not-send="true" class="moz-txt-link-freetext">https://lists.cuis.st/mailman/listinfo/cuis-dev</a> </blockquote> </div> </div> </blockquote> <pre class="moz-signature" cols="72"></pre> </body></html>