<div dir="auto">Right, good point! Fortunately, messages with multiple return values are not very common in my system, I just have a few examples, and I’ll rewrite them with Juan’s suggestion, and I’ll keep your point in mind.</div><div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 23 Jun 2023 at 21:33 Nicolas Cellier <<a href="mailto:nicolas.cellier.aka.nice@gmail.com">nicolas.cellier.aka.nice@gmail.com</a>> wrote:<br></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 dir="ltr"><div>Hi all,</div><div>please note that the keyword message did eliminate the positional semantics found in almost every other language.</div><div>With multiple return arguments, as well as multiple arguments block workaround, we are back to a kind of positional semantic.</div><div>Of course, there is still some name used as block args [:g :s :t | ...] but nothing would tell that [:t :g :s | ...] is a mistake.</div><div>A hint on order can be given by the keyword used to pass block argument, like qr: [:quo :rem | ] or whatever, but when there is more than 2, naming is getting difficult.</div></div><div dir="ltr"><div>Nicolas<br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Le ven. 23 juin 2023 à 21:00, rabbit via Cuis-dev <<a href="mailto:cuis-dev@lists.cuis.st" target="_blank">cuis-dev@lists.cuis.st</a>> a écrit :<br></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>
<p>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?<br>
</p>
<p>I appreciate you,<br>
rabbit</p>
<p><img src="cid:188e9b59e38f1c30fdc1" alt="" style="width:1180px;max-width:100%"></p>
<p><br>
</p>
<div>On 6/22/23 16:21, rabbit via Cuis-dev
wrote:<br>
</div>
<blockquote type="cite">
<p>Hey! I got inspired by your proposal, Luciano, and here's my
solution in eventual promises. Code can be loaded as:</p>
<blockquote>
<p>Installer ss project: 'Cryptography'; install:
'ProCrypto.release.3'.<br>
</p>
</blockquote>
<p>I added a test method <br>
</p>
<blockquote>
<p>RefsTest>>#testMultiReturns<br>
<br>
| selectCount unionFlag pair |<br>
unionFlag := false.<br>
selectCount := 0.<br>
((pair := self promiseResolverPair) key xgcd: 9) <br>
<<* [:each | selectCount := selectCount + 1.
Transcript cr; show: 'each = ', each];<br>
<<* [:g :s :t | unionFlag := true. Transcript
cr; show: 'g = ', g, '; s = ', s, '; t = ', t. g + s + t].<br>
pair value resolve: 21.<br>
(Delay forMilliseconds: 333) wait.<br>
self assert: (selectCount == 3).<br>
self assert: (unionFlag).</p>
</blockquote>
<p>This calls new multireturn #xgcd: method</p>
<blockquote>
<p>xgcd: anInteger<br>
" 21 xgcd: 9"<br>
| g s t |<br>
g := self gcd: anInteger.<br>
s := self / g.<br>
t := anInteger / g.<br>
^ { g. s. t}<br>
</p>
</blockquote>
<p>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.</p>
<blockquote>
<p>Object>>#<<* continuation<br>
<br>
(continuation numArgs == 1)<br>
ifTrue: [^ self whenResolved: [:result | result do:
[:each | continuation value: each]]].<br>
^ self whenResolved: [:result | continuation
valueWithArguments: result].</p>
</blockquote>
<p>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:</p>
<p>Here are 2 return handlers, <br>
</p>
<blockquote>
<p>promise := ((pair := self promiseResolverPair) key xgcd: 9).</p>
</blockquote>
<p>the first for each argument <br>
</p>
<blockquote>
<p>promise <<* [:each | selectCount := selectCount + 1.
Transcript cr; show: 'each = ', each];</p>
</blockquote>
<p>and the second for all three arguments.</p>
<blockquote>
<p>promise <<* [:g :s :t | unionFlag := true. Transcript
cr; show: 'g = ', g, '; s = ', s, '; t = ', t. g + s + t].</p>
</blockquote>
<pre cols="72" style="font-family:monospace">--
❤️🔥🐰
</pre>
<div>On 6/21/23 09:44, Luciano
Notarfrancesco via Cuis-dev wrote:<br>
</div>
<blockquote type="cite">
<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"><br>
</div>
<div><br>
<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" target="_blank">cuis-dev@lists.cuis.st</a>>
wrote:<br>
</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 lang="DE">
<div>
<p class="MsoNormal"><span lang="EN-CA">I added
something similar to my Values package (VW and
ports).</span></p>
<p class="MsoNormal"><span lang="EN-CA">The source is</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA">SequenceableCollection>>asArgumentsIn:
aBlock</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> "Evaluate aBlock with the
receiver's elements as parameters.</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> aBlock takes its arguments from
the receiver.</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> 'ok'</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> #(1 2 3) asArgumentsIn: [:a :b
:c | a + b + c]</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> #(1 2 3) asArgumentsIn: [:a :b |
a + b]</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> #(1 2 3) asArgumentsIn: [:a | a]</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> #(1 2 3) asArgumentsIn: [42]</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> 'not ok'</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> #(1 2 3) asArgumentsIn: [:a :b
:c :d | a + b + c + d]</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> "</span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> </span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-family:"Courier New"" lang="EN-CA"> ^aBlock cullWithArguments: self
asArray</span><span lang="EN-CA"></span></p>
<p class="MsoNormal"><span lang="EN-CA"> </span></p>
<p class="MsoNormal"><span lang="EN-CA">The difference
is that it takes a list of any size and picks out
the first items and binds them to the variables.</span></p>
<p class="MsoNormal"><span lang="EN-CA">I use it often
for CSV processing like</span></p>
<p class="MsoNormal"><span lang="EN-CA">
</span><span lang="EN-CA">(line tokensBasedOn: $;)
asArgumentsIn: [:first :second :y | … ].</span></p>
<p class="MsoNormal"><span lang="EN-CA"> </span></p>
<p class="MsoNormal"><span lang="EN-CA">I am just a
bit unhappy with the name – it is too long. It
reads ok though.</span></p>
<p class="MsoNormal"><span lang="EN-CA">The pipe
character is an interesting idea. I have to think
about it.</span></p>
<p class="MsoNormal"><span lang="EN-CA"> </span></p>
<p class="MsoNormal"><span lang="EN-CA">I am use it
for a while now and I am very happy with it.</span></p>
<p class="MsoNormal"><span lang="EN-CA"> </span></p>
<p class="MsoNormal"><span lang="EN-CA">Happy hacking,</span></p>
<p class="MsoNormal"><span>Christian</span></p>
</div>
</div>
<div lang="DE">
<div>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span> </span></p>
<div style="border-width:1pt medium medium;border-style:solid none none;padding:3pt 0cm 0cm;border-color:rgb(225,225,225) currentcolor currentcolor">
<p class="MsoNormal"><b>Von:</b> Cuis-dev <<a href="mailto:cuis-dev-bounces@lists.cuis.st" target="_blank">cuis-dev-bounces@lists.cuis.st</a>>
<b>Im Auftrag von </b>Luciano Notarfrancesco via
Cuis-dev<br>
<b>Gesendet:</b> Mittwoch, 21. Juni 2023 15:13<br>
<b>An:</b> Discussion of Cuis Smalltalk <<a href="mailto:cuis-dev@lists.cuis.st" target="_blank">cuis-dev@lists.cuis.st</a>><br>
<b>Cc:</b> Luciano Notarfrancesco <<a href="mailto:luchiano@gmail.com" target="_blank">luchiano@gmail.com</a>><br>
<b>Betreff:</b> [Cuis-dev] Methods that return
multiple values</p>
</div>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Smalltalk doesn’t have a
convention for methods returning multiple values,
and I’m not aware of any implementation.</p>
<div>
<p class="MsoNormal">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</p>
</div>
<div>
<p class="MsoNormal"> ^ {g. s. t}</p>
</div>
<div>
<p class="MsoNormal">But using sending messages that
return multiple values is kind of annoying, I end
up doing something like:</p>
</div>
<div>
<p class="MsoNormal"> xgcd := a xgcd: b.</p>
</div>
<div>
<p class="MsoNormal"> g := xgcd at: 1.</p>
</div>
<div>
<p class="MsoNormal"> s := xgcd at: 2.</p>
</div>
<div>
<p class="MsoNormal"> t := xgcd at: 3</p>
</div>
<div>
<p class="MsoNormal">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:</p>
</div>
<div>
<p class="MsoNormal"> (a xgcd: b) | [:g :s :t| …
]</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">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?</p>
</div>
</div>
</div>
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