[Cuis-dev] feedback on simple code

[Ezequiel Birman]

>
> Ah! I did not know that I could use `self` to refer to the class in a
> class method

 Everything you can do on the instance side you can also do over the class
side, it is the same, only shifted by one metalevel.

I didn't know I could return early in a method
>
Non-local return seems to fit Smalltalk. Also sparks lots of debate
<http://lambda-the-ultimate.org/node/2009> for some reason. Does anybody
know where and when the term “full closure” was coined?

-- 
Eze

On Thu, 6 Jun 2024 at 14:09, Mark Volkmann via Cuis-dev <
cuis-dev at lists.cuis.st> wrote:

> Andres, thank you so much for the feedback! I didn't know I could return
> early in a method like you showed and hadn't considered the difference
> between / and //.
>
> On Wed, Jun 5, 2024 at 5:37 PM Andres Valloud via Cuis-dev <
> cuis-dev at lists.cuis.st> wrote:
>
>> Hi, ifTrue: is supposed to take a block argument, so it should be
>> ifTrue: [nil].  And to prevent indenting the entire method, consider
>>
>>         self < 1 ifTrue: [^nil].
>>         ... etc...
>>         ^seq
>>
>> It's perfectly fine to have multiple return statements.
>>
>> By the way, use // 2 instead of / 2, because / 2 will try to make a
>> fraction to then discover that next was even.  But now you know next is
>> even, so you can do next // 2.  Using / is still correct of course.
>>
>> I wouldn't worry about doing bitShift: -1 instead of // 2 here.  That
>> kind of "speedup" is barking at the wrong forest (not even the wrong
>> tree) from the perspective of Collatz.  I would familiarize myself with
>> the difference between the pairs "//, \\", "quo:, rem:", and "div:,
>> mod:", however.
>>
>> On 6/5/24 11:16 AM, Mark Volkmann via Cuis-dev wrote:
>> > I took another shot at simplifying the code. I didn't need to use
>> > recursion. I can do this instead as an instance method added to the
>> > Integer class:
>> >
>> > collatz
>> >      "answers an OrderedCollection containing the Collatz sequence for
>> > this integer"
>> >
>> >      | next seq |
>> >      ^self < 1
>> >          ifTrue: nil
>> > ifFalse: [
>> > next := self.
>> > seq := OrderedCollection new.
>> > seq addLast: next.
>> > [next = 1] whileFalse: [
>> > next := next even ifTrue: [next / 2] ifFalse: [next * 3 + 1].
>> > seq addLast: next
>> > ].
>> > ^seq
>> > ]
>> >
>> > Beside the lack of memoization and the "orbit" concept, what would you
>> > change about this?
>> >
>> >
>> > On Wed, Jun 5, 2024 at 12:40 PM Mark Volkmann <
>> r.mark.volkmann at gmail.com
>> > <mailto:r.mark.volkmann at gmail.com>> wrote:
>> >
>> >     See my replies inline below with some parts snipped to focus my
>> replies.
>> >
>> >     On Wed, Jun 5, 2024 at 12:19 PM Andres Valloud via Cuis-dev
>> >     <cuis-dev at lists.cuis.st <mailto:cuis-dev at lists.cuis.st>> wrote:
>> >
>> >         Always be on the lookout for when a receiver is just self.
>> >         Otherwise,
>> >         the code is not using the knowledge it has of where it is
>> >         implemented
>> >         (and this leads to all sorts of problems later).
>> >
>> >
>> >     Ah! I did not know that I could use `self` to refer to the class in
>> >     a class method.
>> >
>> >         Also, you can accomplish the same with much less code.  Any time
>> >         you
>> >         have a class whose class methods offer a "service" but do not
>> >         really
>> >         have instances, you should suspect the code should be placed
>> >         elsewhere.
>> >
>> >
>> >     I see that I don't need the next: method and can just move that code
>> >     in the gather:seq: method.
>> >     But it's not apparent to me what else I can do to make the code
>> shorter.
>> >
>> >         Side comment: I've been working on the Collatz problem for a
>> *long*
>> >         time, so I have quite a few opinions on how to go about writing
>> >         specifically this code...
>> >
>> >
>> >     I know I could add caching of results to make subsequent calls with
>> >     different integers much faster.
>> >
>> >         But in this particular case, what you're collecting is the orbit
>> >         of an
>> >         integer (so, anInteger, not aNumber).
>> >
>> >
>> >     Excellent point! I changed every occurrence of `aNumber` to
>> >     `anInteger` in my code.
>> >
>> >     --
>> >     R. Mark Volkmann
>> >     Object Computing, Inc.
>> >
>> >
>> >
>> > --
>> > R. Mark Volkmann
>> > Object Computing, Inc.
>> >
>> --
>> Cuis-dev mailing list
>> Cuis-dev at lists.cuis.st
>> https://lists.cuis.st/mailman/listinfo/cuis-dev
>>
>
>
> --
> R. Mark Volkmann
> Object Computing, Inc.
> --
> Cuis-dev mailing list
> Cuis-dev at lists.cuis.st
> https://lists.cuis.st/mailman/listinfo/cuis-dev
>
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