One factor is whether you consider the version to be discrete values or a
structured format for data - I'd argue that we have a structured format
due to the expectation that future versions of the HTTP spec could arrive.
Adding conformance to Hashable/Equatable and CustomStringConvertible
provides the operations, and whilst it may look strange we could also
provide convenience constants if it makes sense, ie:
public static let http1_0 = HTTPVersion(major: 1, minor: 0)
public static let http1_1 = HTTPVersion(major: 1, minor: 1)
public static let http2_0 = HTTPVersion(major: 2, minor: 0)
Having said that, there is slight additional storage overhead for structs
vs. enums, as a slight additional compare cost.
Chris
To: Rien <Rien@Balancingrock.nl>
Cc: Chris Bailey <BAILEYC@uk.ibm.com>, swift-server-dev@swift.org
Date: 14/06/2017 08:12
Subject: Re: [swift-server-dev] Convert HTTPVersion to struct
I think currently the http version is come from the http_parser
which has parsed the version string to number anyway. hence the
performance should be similar.
I do see some advantage to use struct tho, for example comparing
only major version.
Michael
>
> The choices seem to be:
>
> 1) String
> 2) Enum
> 3) Tuple
> 4) Struct
> 5) Class
>
> 1) String
> Advantage: it is in fact an utf-8 string. No conversions needed.
> Disadvantage: It is mostly thought of as a number, thus the
abstraction does not match the type, very minor performance penalty
in comparing. Illogical to add HTTP-version extensions to the type.
>
> 2) Enum
> Advantage: shortest possible representation (?), fastest compare
(?), easy to use.
> Disadvantage: Needs converting to and from.
>
> 3) Tuple
> Advantage: Matches fairly wel with the abstraction.
> Disadvantage: Fairly complex conversion, adding members/operations
is non-intuitive, not very easy to use.
>
> 4) Struct
> Advantage: Matches fairly wel with the abstraction.
> Disadvantage: Fairly complex conversion. Not very easy to use
without adding members/operations.
>
> 5) This was for completeness only, I would be very surprised if
anybody would actually propose this… ;-)
>
>
> To me that leaves option 2 and 4.
> Advantage of 2 over 4:
>
> - I find the abstraction a better match. The difference between 1,
1.1 and 2 is such that it makes little sense to be to differentiate
based on the numerical values. It makes much more sense to
differentiate based on the “whole number”. AFAIIC they could just as
easily have named the versions A, B, C etc. The numbers do not
convey any information as such.
> - Switch is easier and more intuitive to use.
> - Enums can have additional properties and operations similar to
struct.
>
> Advantage of 4 over 2:
> I don’t see any.
>
> Regards,
> Rien
>
> Site: http://balancingrock.nl
> Blog: http://swiftrien.blogspot.com
> Github: Balancingrock (Rien) · GitHub
> Project: http://swiftfire.nl - An HTTP(S) web server framework in
Swift
>
>
>
>>
>> Based on our discussed approach of reviewing each of the types in
the HTTP project, I've raised the following PR to convert
HTTPVersion from (Int, Int) to a struct based on Paulo's proposal:
>> Convert HTTPVersion to a struct by seabaylea · Pull Request #6 · swift-server/http · GitHub
>>
>> I've not yet added Hashable, Equatable and
CustomStringConvertible protocols - we can do that if we're happy
with the change.
>>
>> Chris
>> Unless stated otherwise above:
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>
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Unless stated otherwise above:
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···
Michael Chiu <hatsuneyuji@icloud.com> wrote on 14/06/2017 08:12:35: > From: Michael Chiu <hatsuneyuji@icloud.com>
> On Jun 13, 2017, at 11:41 PM, Rien via swift-server-dev <swift- > server-dev@swift.org> wrote:
>> On 13 Jun 2017, at 22:44, Chris Bailey via swift-server-dev > <swift-server-dev@swift.org> wrote:
