Add S.fromEither to pull out values from either

[wennergr]

S.fromEither :: b -> Either a b -> b

Closes: #130

[davidchambers]

Thank you, @wennergr! This was a nice surprise. :)

[davidchambers]

The order in which the functions appear in the source file determines the order in which the functions are listed in the documentation, so it's nice to group related functions. In this case, let's follow the (somewhat arbitrary) precedent set by fromMaybe—which appears after isJust and before maybe—by inserting fromEither between isRight and either.

[davidchambers]

Let's adjust the indentation like so:

throws(function() { S.fromEither(0, [1, 2, 3]); },
       'Invalid value\n' +

[wennergr]

Thanks for your feedback

I did not do property based tests because the fromMaybe tests didn't. Is it only used to test laws? Performance reasons? More then happy to change ;)

Also more then happy to rebase before the merge.

[davidchambers]

I did not do property based tests because the fromMaybe tests didn't. Is it only used to test laws?

The truthful answer is that property-based testing is still relatively new to me, so I don't think to use it. While it would be great to add more property-based tests, that's a larger change orthogonal to this one.

Also more then happy to rebase before the merge.

That would be marvellous. :)

I'd like to add that I ❤️ the way in which you went about this pull request. You matched the existing code and documentation style, and referenced the issue this pull request will close. Very nice!

[wennergr]

Done, and thanks!

[davidchambers]

🌳

[davidchambers]

$ npm install [email protected]

$ node
> const S = require('sanctuary')
undefined
> S.fromEither
fromEither :: b -> Either a b -> b