Enable adding multiple routers

[lionhylra]

Create a function to enable add batch handlers.
Use case:

server.appendRoutes([
            "/fish/accepted" => ClosureHTTPHandler { _ in
                HTTPResponse.make(statusCode: .accepted)
            },
            "/fish/*" => .file(named: "fish.json", in: .module)
        ])

[codecov]

Codecov Report

Merging #7 (64134b0) into main (e103d82) will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main       #7      +/-   ##
==========================================
+ Coverage   89.60%   89.68%   +0.08%     
==========================================
  Files          29       29              
  Lines        1087     1096       +9     
==========================================
+ Hits          974      983       +9     
  Misses        113      113              

Impacted Files	Coverage Δ
Sources/HTTPServer.swift	94.61% <100.00%> (+0.26%)	⬆️
Sources/Handlers/RoutedHTTPHandler.swift	66.66% <100.00%> (+3.70%)	⬆️

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[lionhylra]

There is a concern for this PR. This library defines a custom operator "=>", if a project that defining same operator or imports a library that defines same operator, there could be conflicts.

[lionhylra]

Verified that defining custom operators in both project and library won't cause conflicts. They are just like method overloads.

[swhitty]

Thanks for you PR @lionhylra. It is an interesting idea and we should think about it.

IMO the operator => is clear but I am unsure how common it is, and maybe a label verb to: is just as concise.

The existing syntax is OK;
.appendRoute("/fish/*", to: .file(named: "fish.json", in: .module))

I know we have had discussions offline about how we could possible use a @resultBuilder to declare these things — It would be interesting to see what the limitations of that approach is.

[lionhylra]

Thanks for you PR @lionhylra. It is an interesting idea and we should think about it.

IMO the operator => is clear but I am unsure how common it is, and maybe a label verb to: is just as concise.

The existing syntax is OK; .appendRoute("/fish/*", to: .file(named: "fish.json", in: .module))

I know we have had discussions offline about how we could possible use a @resultBuilder to declare these things — It would be interesting to see what the limitations of that approach is.

I kind of agree. Personally I think word expression is always better than operator, like you said using verb label to. Adding operator "=>" is something nice to have to allow users to make nice router mappings, but it is not required in library.
I also think resultBuilder is not suitable for this use case and it's overkill.