Alternatives to sum types in Go

making.pusher.com

5 points by willsewell 8 years ago · 2 comments

Reader

Good post! Crossposting my comment from that other crusty news aggregator:

Alternative 1a is to use Alternative 1 with https://github.com/BurntSushi/go-sumtype /plug

go-sumtype requires the interface to be sealed (which you're already doing) and one small annotation:

    //go-sumtype:decl TheInterfaceName

Then you just run `go-sumtype`

    $ go-sumtype $(go list ./... | grep -v vendor)

and it will do exhaustiveness checks in any type switch in which `TheInterfaceName` participates. This will prevent the "For example, during a refactor a handler might be removed but a type that implements the interface is not." failure mode mentioned in the article.

willsewellOP 8 years ago

Somewhat off topic, but the idea to show the examples as diffs against the prior one was based on this block post: https://jameshfisher.com/2017/11/23/diff-views.

I would be interested to hear people's thoughts on the effectiveness. I like how it is clear what is important in each example, but there is perhaps too much noise and it's a shame the regular syntax highlighting does not work.

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Alternatives to sum types in Go

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