[swift-server-dev] Convert HTTPVersion to struct

[Rien]

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: http://github.com/Balancingrock
Project: http://swiftfire.nl - An HTTP(S) web server framework in Swift



> On 13 Jun 2017, at 22:44, Chris Bailey via swift-server-dev <swift-server-dev at swift.org> wrote:
> 
> 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: 
>         https://github.com/swift-server/http/pull/6 
> 
> I've not yet added Hashable, Equatable and CustomStringConvertible protocols - we can do that if we're happy with the change. 
> 
> Chris
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