2017-11-05 20:11 GMT+01:00 Denis Kudriashov <dionisiydk@gmail.com>:
2017-11-05 18:41 GMT+01:00 Nicolas Cellier <nicolas.cellier.aka.nice@ gmail.com>:
As for -1 , 0 , 1, we must encode 3 possible results:
value1 is before value2 (<) value1 is same rank as value2 (=) value1 is after value2 (>)
While it is well known comparison logic I would like to find better name than #compare/collate which reflects explicitly what you just described. Something like:
sortFunction rank: anObject1 comparedTo: anObject2
And according to this the current #threeWayCompareTo: can be renamed too:
anObject rankComparedTo: anObject2
Another idea is to have explicit meaning in the method name that it defines ascending order of receiver compared to argument. I am always confused when I need to implement a new block for sorted collection. I am usually not know what result I will have: will it be ascending or descending. Because block itself has no meaning about it and it only returns true or false. Same confusion could happen during implementation of new #threeWayCompareTo: method. So I would use something like:
anObject rankInAscendingOrderTo: anObject2
Maybe it is bad in english. But I hope it shows my idea. So if you like it, try suggest better names.
Denis, you already know my opinion, but if you insist on a new selector, then I'm proposing <,=,> anObject "Answer the direction for collating self and anObject. The direction is -1 is self is to be collated to the left (self < anObject) 0 if self and anObject have same rank (self = anObject) 1 if self is to be collated to the right (self > anObject)" ...snip...
Using numbers -1,0,+1 to encode these results is clever, because it's trivial to revert the order (just take the opposite, or multiply by -1) So it's widespread in programming community, it's cultural
We could use any other convention like Symbols #(< = >), that would convey a bit more meaning, but there's no need to go against culture if we have no superior solution (wrt inversion)
2017-11-05 18:30 GMT+01:00 Nicolas Cellier <nicolas.cellier.aka.nice@gmai l.com>:
Hi Stef
Collation is the accurate and correct term If I google: Unicode comparison algorithm for example, the first hit is: UTS #10: Unicode Collation Algorithm - Unicode.org http://unicode.org/reports/tr10/
collationner (collate) has a second meaning, even in French: https://fr.wiktionary.org/wiki/collationner
Interestingly, the wikipedia page https://en.wikipedia.org/wiki/ Collation isn't even translated in French... Maybe i's not popular enough in French (un mot savant)... I'm not good enough in English to tell if it has same "snob" connotation
Nicolas
2017-11-05 17:49 GMT+01:00 Stephane Ducasse <stepharo.self@gmail.com>:
Hi nicolas
where it is defined that collation is something returning -1, 0, 1? I'm always thinking to newcomers that have to learn yet another concept and here for nothing. Because SortFunction with a nice comment saying that it should return -1, 0, 1 looks simpler that CollatorFunction which tells me nothing, except that may be this is about drinking (for french).
Stef
On Sun, Nov 5, 2017 at 3:47 PM, Nicolas Cellier <nicolas.cellier.aka.nice@gmail.com> wrote:
2017-11-05 10:16 GMT+01:00 Esteban Lorenzano <estebanlm@gmail.com>:
On 5 Nov 2017, at 06:00, Stephane Ducasse <stepharo.self@gmail.com
wrote:
Hi guys
Why do we rename class Sort to introduce terms that have unknown, unclear, undocumented meaning?
+1
To me PluggableSortFunction is MUCH better than
CollatorBlockFunction.
but pluggable is also bad, IMO. also I see there is some incoherence in the names:
agree with Esteban, Pluggable pouah!
ChainedSortFunction -> this is kind of ok, but I think a âComposedSortFunctionâ is better.
But there can be several kind of composition... For example wrapped as illustrated with UnderfinedSorter refactoring that I proposed. Personnally I like Chained because it explicitely tells the kind of composition
SortByPropertyFunction -> shouldnât be âPropertySortFunctionâ ? (coherent with the previous one)
+1 for PropertySortFunction, or maybe just PropertySorter
CollatorSortFunction -> this is like a âBlockSortFunctionâ or âValuableSortFunctionâ ?
CollatorBlockFunction is only a proxy to the block so as it answers to #threeWayCompare:with: protocol rather than value:value: It's a Block view as a CollatorFunction. The name first surprised me negatively, but after reflexion it tells what it is.
1) Collator indicates that the block (valuable) will return -1, 0 or +1
2) It's not necessarily a block, it could be anything understanding value:value: But, the valuable should return -1,0,+1, so apart <=> (threeWayCompareTo:) it ain't gonna be anything but a block in practice. For <=> we would want a DefaultSortFunction and would not use a CollatorBlockFunction.
3) Function refers to SortFunction. For this, I'm neutral, whether you call it Sorter or SortFunction I don't care. SortFunction kind of implies these are stateless, so it's a rather good and accurate name. Maybe a Sorter could be more confusing, because a Sorter could be thought as having the sorted collection as instance variable (statefull).
Nicolas
Esteban
Stef