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@lists.squeakfoundation.org im Auftrag von Levente Uzonyi leves@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@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!