-Dave > On Dec 31, 2015, at 12:28 AM, Jacob Bandes-Storch <[email protected]> wrote: > > With the optimizer as it is today, if this were @_transparent could the extra > function invocation(s) be optimized out when you use it in a non-escaping > context such as sort()?
Sure. It doesn’t need to be @_transparent; in general use @inline(__always) instead except in very special cases, (e.g. when you need constant folding to propagate through the function so you can give arithmetic overflow diagnostics at compile-time). > > Jacob > > On Thu, Dec 31, 2015 at 12:26 AM, Dave Abrahams via swift-evolution > <[email protected] <mailto:[email protected]>> wrote: > You don’t. Is that a problem for the intended use-cases? > > -Dave > >> On Dec 31, 2015, at 12:11 AM, Susan Cheng <[email protected] >> <mailto:[email protected]>> wrote: >> >> And how do you write a @noescape version with this function? >> >> Dave Abrahams <[email protected] <mailto:[email protected]>> 於 >> 2015年12月31日星期四 寫道： >> I don’t understand that argument. Obviously the function would be >> documented and there would be examples showing how to use it. Why would it >> confuse people? >> >> I think you’d need much stronger reasons to justify adding an unbounded set >> of overloads (is every algorithm that takes a comparison closure going to >> get one of these?) when we can handle the problem economically with a single >> function. >> >> -Dave >> >>> On Dec 31, 2015, at 12:04 AM, Susan Cheng <[email protected] <>> wrote: >>> >>> It confuses people if provide a global function byComparing in stdlib >>> which's doing nothing alone. >>> >>> Dave Abrahams <[email protected] <>> 於 2015年12月31日星期四 寫道： >>> Why add all those algorithms when you can write this >>> >>> func byComparing<T, U: Comparable>(getComparisonKey: (T)->U) -> (T, T) -> >>> Bool { >>> return { getComparisonKey($0) < getComparisonKey($1) } >>> } >>> >>> peoples.sort(byComparing { $0.name <http://0.name/> }) >>> >>> ? >>> >>> -Dave >>> >>>> On Dec 30, 2015, at 10:38 PM, Susan Cheng via swift-evolution >>>> <[email protected] <>> wrote: >>>> >>>> >>>> Consider the follows: >>>> >>>> struct Person { >>>> >>>> var name: String >>>> var age: Int >>>> } >>>> >>>> let peoples = [Person(name: "Hawk", age: 24), Person(name: "Andrew", age: >>>> 23)] >>>> >>>> let youngest = peoples.minElement { $0.age < $1.age } >>>> >>>> print(youngest?.name) >>>> >>>> it's silly that we always have to write the code like { $0.some < $1.some >>>> } or { some($0) < some($1) } >>>> >>>> so, we should add those methods to stdlib: >>>> >>>> extension SequenceType { >>>> /// Returns the minimum element in `self` or `nil` if the sequence is >>>> empty. >>>> /// >>>> /// - Complexity: O(`elements.count`). >>>> /// >>>> @warn_unused_result >>>> public func minElement<R : Comparable>(@noescape by: >>>> (Generator.Element) throws -> R) rethrows -> Generator.Element? { >>>> return try self.minElement { try by($0) < by($1) } >>>> } >>>> /// Returns the maximum element in `self` or `nil` if the sequence is >>>> empty. >>>> /// >>>> /// - Complexity: O(`elements.count`). >>>> /// >>>> @warn_unused_result >>>> public func maxElement<R : Comparable>(@noescape by: >>>> (Generator.Element) throws -> R) rethrows -> Generator.Element? { >>>> return try self.maxElement { try by($0) < by($1) } >>>> } >>>> } >>>> >>>> public extension MutableCollectionType { >>>> >>>> /// Return an `Array` containing the sorted elements of `source`. >>>> /// according to `by`. >>>> /// >>>> /// The sorting algorithm is not stable (can change the relative order >>>> of >>>> /// elements that compare equal). >>>> @warn_unused_result(mutable_variant="sortInPlace") >>>> func sort<R : Comparable>(@noescape by: (Generator.Element) -> R) -> >>>> [Generator.Element] { >>>> return self.sort { by($0) < by($1) } >>>> } >>>> } >>>> >>>> public extension MutableCollectionType where Self.Index : >>>> RandomAccessIndexType { >>>> >>>> /// Sort `self` in-place according to `by`. >>>> /// >>>> /// The sorting algorithm is not stable (can change the relative order >>>> of >>>> /// elements that compare equal). >>>> mutating func sortInPlace<R : Comparable>(@noescape by: >>>> (Generator.Element) -> R) { >>>> self.sortInPlace { by($0) < by($1) } >>>> } >>>> } >>>> >>>> _______________________________________________ >>>> swift-evolution mailing list >>>> [email protected] <> >>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>> >> > > > _______________________________________________ > swift-evolution mailing list > [email protected] <mailto:[email protected]> > https://lists.swift.org/mailman/listinfo/swift-evolution > <https://lists.swift.org/mailman/listinfo/swift-evolution>
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