[swift-evolution] TrigonometricFloatingPoint/MathFloatingPoint protocol?

[Xiaodi Wu]

So, this has been discussed before on the list many times in the past. The
core team has stated that their preferred process for this is to have
individuals write their own libraries, get real-world adoption, then (as
consensus emerges) propose their inclusion as a core library.

Keep in mind that the _standard_ library is what's available by default
without importing anything; it is deliberately small and includes only the
most basic types that need compiler support. This is different to be
distinguished from core libraries like Foundation and Dispatch.

With that exhortation in mind, I have written a math library that provides
protocol-based trigonometry. For expediency it wraps Darwin or Glibc at the
moment. It is intended to be an exercise in creating a plausible design
that respects existing Swift conventions. On top of that, it includes
implementations for complex and rational numbers, as well as pseudorandom
number generators (unfinished at the moment); I include the link here as a
reply regarding what I feel would be the optimal design (in terms of free
function vs. members) for such a math protocol:

https://github.com/xwu/NumericAnnex


On Mon, Jul 31, 2017 at 7:37 PM, Taylor Swift via swift-evolution <
swift-evolution at swift.org> wrote:

> I’d be completely in favor of this. Structs for priority queues,
> skiplists, trees, binary search and more sorting functions would also be on
> my wishlist. I think Python made a very good choice in choosing to vend
> separate standard modules for stuff like that  instead of bloating its
> builtin namespace.
>
> On Mon, Jul 31, 2017 at 2:22 PM, Hooman Mehr <hooman at mac.com> wrote:
>
>> Maybe we need more than one level of standard library: The core (which is
>> most of what we have now (but maybe not all of it) and multiple opt-in
>> standard modules for hash functions, math, specialized data structures, etc.
>>
>> On Jul 31, 2017, at 11:10 AM, Taylor Swift <kelvin13ma at gmail.com> wrote:
>>
>> I’m not sure why only the stdlib is inlineable and specializable, but I
>> believe it has something to do with ABI. I’m not an ABI expert though. I
>> strongly disagree that a Swift Math library should be delegated to a third
>> party. Math is “common” enough that there should really only be one
>> “standard” implementation of it, under the direction of the Swift Project;
>> we don’t want 5 competing third party Vector standards.
>>
>> On Mon, Jul 31, 2017 at 2:02 PM, Hooman Mehr <hooman at mac.com> wrote:
>>
>>> I know. I hear you. I have some special arrangmnents to keep such things
>>> manageable, and I am not happy about how things stand right now.
>>>
>>> What I am hoping to open up stdlib special compiler mode to other
>>> (low-level) libraries and also letting such libraries gain optimizations
>>> similar to stdlib when included in a project.
>>>
>>> So, instead of putting things in stdlib, I want stdlib’s special
>>> privileges being made available to a certain category of third-party or
>>> internal modules.
>>>
>>>
>>> On Jul 31, 2017, at 10:54 AM, Taylor Swift <kelvin13ma at gmail.com> wrote:
>>>
>>> Isn’t the point of standard inlineable library module to prevent the
>>> need to copy and paste code like this into every project? Currently I have
>>> a “math.swift” file I copy and paste into all of my projects, and since I
>>> occasionally update it, there exists about 15 different versions of it
>>> floating around, so I know this is not a sustainable practice.
>>>
>>> On Mon, Jul 31, 2017 at 1:45 PM, Hooman Mehr <hooman at mac.com> wrote:
>>>
>>>> I prefer an approach that preserves how I am used to seeing math
>>>> expressions. I use this myself:
>>>>
>>>> protocol FloatingPointMath: FloatingPoint
>>>> {
>>>>     static func sqrt(_ value: Self) -> Self
>>>>
>>>>     static func sin(_ value: Self) -> Self
>>>>     static func cos(_ value: Self) -> Self
>>>>     static func tan(_ value: Self) -> Self
>>>>     static func asin(_ value: Self) -> Self
>>>>     static func acos(_ value: Self) -> Self
>>>>     static func atan(_ value: Self) -> Self
>>>>
>>>>     static func ln(_ value: Self) -> Self
>>>>     static func log(_ value: Self, base: Self) -> Self
>>>>     static func pow(_ value: Self, exponent:Self) -> Self
>>>>     static func exp(_ value: Self) -> Self
>>>> }
>>>>
>>>> It does not pollute the global namespace and gives nice contextual
>>>> auto-completion.  And I don’t want it in the standard library: I only add
>>>> the file when I need it. (it is not a separate module for optimization
>>>> reasons).
>>>>
>>>> On Jul 31, 2017, at 10:29 AM, Taylor Swift via swift-evolution <
>>>> swift-evolution at swift.org> wrote:
>>>>
>>>>
>>>>
>>>> On Mon, Jul 31, 2017 at 1:23 PM, Adrian Zubarev <
>>>> adrian.zubarev at devandartist.com> wrote:
>>>>
>>>>> I’m not sure how I would feel about this. To be honest I’d avoid such
>>>>> additional changes from the stdlib, because they really don’t belong there.
>>>>> Instead some `Math` module/package would be a better fit than clustering
>>>>> everything into stdlib until we end up also adding UI stuff.
>>>>>
>>>>> Furthermore, I don’t think a function would make any sense here. It
>>>>> really should be a computed property.
>>>>>
>>>>>
>>>>>
>>>> I think a standard Math module would be a good idea, but only if it
>>>> benefits from the same inlining and specialization as the standard library.
>>>> Also squareRoot() should be moved to the Math module if it is ever created.
>>>>
>>>>
>>>>> Am 31. Juli 2017 um 19:03:49, Taylor Swift via swift-evolution (
>>>>> swift-evolution at swift.org) schrieb:
>>>>>
>>>>> How would people feel about adding a protocol
>>>>>
>>>>> protocol MathFloatingPoint:FloatingPoint
>>>>> {
>>>>>     func sin() -> Self
>>>>>     func cos() -> Self
>>>>>     func tan() -> Self
>>>>>     func asin() -> Self
>>>>>     func acos() -> Self
>>>>>     func atan() -> Self
>>>>>
>>>>>     func ln() -> Self
>>>>>     func log(base:Self) -> Self
>>>>>     func pow(exponent:Self) -> Self
>>>>>     func exp() -> Self
>>>>> }
>>>>>
>>>>> to the standard library? Float and Double would then be made to
>>>>> conform by default using Swift implementations instead of having to import
>>>>> Glibc / Darwin and writing the extensions, depending on platform.
>>>>> _______________________________________________
>>>>> swift-evolution mailing list
>>>>> swift-evolution at swift.org
>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>>>
>>>>>
>>>> _______________________________________________
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>>>> swift-evolution at swift.org
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>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
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