Hi Levente,


alright, I'll try to measure and optimize them again.


> Two things I saw and you didn't mention are block creation

You mean that "ifNone: [0]"? One could replace it with "ifNone: 0" to avoid duplication.

> and introduction of non-jittable comparison.

What are you referring to?

Best,
Christoph

________________________________
Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von Levente Uzonyi <leves at caesar.elte.hu>
Gesendet: Montag, 17. Februar 2020 01:00:11
An: The general-purpose Squeak developers list
Betreff: Re: [squeak-dev] The Inbox: Collections-ct.875.mcz

Hi Christoph,

On Sun, 16 Feb 2020, Thiede, Christoph wrote:

>
> Hi Levente,
>
>
> thanks for the suggestions.
>
>
> > And one more thing: These method resemble #indexOf:* methods, so I think #ifAbsent: is a better choice than #ifNone:.
>
>
> Agreed :-)
>
> > I suggest keeping the all method comments
>
> Personally, I see little value in documenting a one-liner. Documentation is useful for explaining and optimized method that does not provide the typical Smalltalk readability. Plus, they all need to be maintained ...

If one sees #findLast: being sent somewhere, and one doesn't know what it
does, with your changes, it means looking up the implementors three times
to get to the actual implementation and comment.

>
> > measuring the performance impact of the rewrite.
>
> What is the critical point here?
> Of course, the stack will be a little higher, but the asymptotic cost does not change. We only evaluate anotherBlock at the end instead of returning 0.

Two things I saw and you didn't mention are block creation and
introduction of non-jittable comparison.

>
> Please do not misunderstand me: I honor optimizing critical Smalltalk methods, but I always strive to avoid premature optimization.

In my opinion, generic library methods like these should be optimized by
definition.

Calling premature optimization means that you assume that if these methods
were written in a more optimal way, then their complexity and/or
legibility would be worse.
Have a look at #indexOf:*, and you'll see that's not the case.

> Should we maybe establish to practice to store such benchmarks somewhere in the trunk so that not every willing contributor needs to write them again?

I think methods like these don't change often enough (presumably they
never change) to justify storing benchmarks for them.


Levente

>
> Best,
> Christoph
>
> _________________________________________________________________________________________________________________________________________________________________________________________________________________________________
> Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von Levente Uzonyi <leves at caesar.elte.hu>
> Gesendet: Sonntag, 16. Februar 2020 22:47:10
> An: The general-purpose Squeak developers list
> Betreff: Re: [squeak-dev] The Inbox: Collections-ct.875.mcz
> And one more thing: These method resemble #indexOf:* methods, so I think
> #ifAbsent: is a better choice than #ifNone:.
>
> Levente
>
> On Sun, 16 Feb 2020, Levente Uzonyi wrote:
>
> > Hi Christoph,
> >
> > I suggest keeping the all method comments, and measuring the performance
> > impact of the rewrite.
> >
> > Levente
> >
> > On Sun, 16 Feb 2020, commits at source.squeak.org wrote:
> >
> >> A new version of Collections was added to project The Inbox:
> >> http://source.squeak.org/inbox/Collections-ct.875.mcz
> >>
> >> ==================== Summary ====================
> >>
> >> Name: Collections-ct.875
> >> Author: ct
> >> Time: 16 February 2020, 3:32:23.116 pm
> >> UUID: 61ea773b-1408-c040-a712-09238ee6fe2f
> >> Ancestors: Collections-topa.873
> >>
> >> Extends and realigns version of #findFirst: and #findLast:.
> >>
> >> =============== Diff against Collections-topa.873 ===============
> >>
> >> Item was changed:
> >>  ----- Method: SequenceableCollection>>findFirst: (in category
> > 'enumerating') -----
> >>  findFirst: aBlock
> >> -     "Return the index of my first element for which aBlock evaluates as
> > true."
> >>
> >> +     ^ self findFirst: aBlock startingAt: 1!
> >> -     | index |
> >> -     index := 0.
> >> -     [(index := index + 1) <= self size] whileTrue:
> >> -             [(aBlock value: (self at: index)) ifTrue: [^index]].
> >> -     ^ 0!
> >>
> >> Item was added:
> >> + ----- Method: SequenceableCollection>>findFirst:ifNone: (in category
> > 'enumerating') -----
> >> + findFirst: aBlock ifNone: anotherBlock
> >> +
> >> +     ^ self findFirst: aBlock startingAt: 1 ifNone: anotherBlock!
> >>
> >> Item was added:
> >> + ----- Method: SequenceableCollection>>findFirst:startingAt: (in category
> > 'enumerating') -----
> >> + findFirst: aBlock startingAt: minIndex
> >> +
> >> +     ^ self findFirst: aBlock startingAt: minIndex ifNone: [0]!
> >>
> >> Item was added:
> >> + ----- Method: SequenceableCollection>>findFirst:startingAt:ifNone: (in
> > category 'enumerating') -----
> >> + findFirst: aBlock startingAt: minIndex ifNone: anotherBlock
> >> +     "Return the index of my first element with index >= minIndex for
> > which aBlock evaluates as true. If no element is found, return the value of
> > anotherBlock."
> >> +
> >> +     | index |
> >> +     index := minIndex - 1.
> >> +     [(index := index + 1) <= self size] whileTrue:
> >> +             [(aBlock value: (self at: index)) ifTrue: [^index]].
> >> +     ^ anotherBlock value!
> >>
> >> Item was changed:
> >>  ----- Method: SequenceableCollection>>findLast: (in category
> > 'enumerating') -----
> >>  findLast: aBlock
> >> -     "Return the index of my last element for which aBlock evaluates as
> > true."
> >>
> >> +     ^ self findLast: aBlock startingAt: 1!
> >> -     | index |
> >> -     index := self size + 1.
> >> -     [(index := index - 1) >= 1] whileTrue:
> >> -             [(aBlock value: (self at: index)) ifTrue: [^index]].
> >> -     ^ 0!
> >>
> >> Item was added:
> >> + ----- Method: SequenceableCollection>>findLast:ifNone: (in category
> > 'enumerating') -----
> >> + findLast: aBlock ifNone: anotherBlock
> >> +
> >> +     ^ self findLast: aBlock startingAt: 1 ifNone: anotherBlock!
> >>
> >> Item was changed:
> >>  ----- Method: SequenceableCollection>>findLast:startingAt: (in category
> > 'enumerating') -----
> >> + findLast: aBlock startingAt: minIndex
> >> - findLast: aBlock startingAt: i
> >> -     "Return the index of my last element with index >= i for which aBlock
> > evaluates as true."
> >>
> >> +     ^ self findLast: aBlock startingAt: minIndex ifNone: [0]!
> >> -     | index |
> >> -     index := self size + 1.
> >> -     [(index := index - 1) >= i] whileTrue:
> >> -             [(aBlock value: (self at: index)) ifTrue: [^index]].
> >> -     ^ 0!
> >>
> >> Item was added:
> >> + ----- Method: SequenceableCollection>>findLast:startingAt:ifNone: (in
> > category 'enumerating') -----
> >> + findLast: aBlock startingAt: minIndex ifNone: anotherBlock
> >> +     "Return the index of my last element with index >= minIndex for which
> > aBlock evaluates as true.  If no element is found, return the value of
> > anotherBlock."
> >> +
> >> +     | index |
> >> +     index := self size + 1.
> >> +     [(index := index - 1) >= minIndex] whileTrue:
> >> +             [(aBlock value: (self at: index)) ifTrue: [^index]].
> >> +     ^ anotherBlock value!
> >
> >
>
>
>
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