# Sum type constructor declaration subtlety (and documentation wanted!)

**URL:** <https://discuss.ocaml.org/t/sum-type-constructor-declaration-subtlety-and-documentation-wanted/1898>\
**Category:** Ecosystem\
**Created:** [April 23, 2018, 3:45pm UTC](https://discuss.ocaml.org/t/sum-type-constructor-declaration-subtlety-and-documentation-wanted/1898 "2018-04-23T15:45:42Z")\
**Posts on this page:** 6\
**Page:** 2

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**Author:** ![Yaron\_Minsky](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/yaron_minsky/32/11_2.png) [@Yaron\_Minsky](https://discuss.ocaml.org/u/Yaron_Minsky)\
**Post date:** [May 4, 2018, 10:39am UTC](https://discuss.ocaml.org/t/sum-type-constructor-declaration-subtlety-and-documentation-wanted/1898/21 "2018-05-04T10:39:50Z")

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RWO now has some coverage of this:

[https://dev.realworldocaml.org/variants.html](https://dev.realworldocaml.org/variants.html)

It’s in the end of the opening section.

y

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**Author:** ![perry](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/perry/32/518_2.png) [@perry](https://discuss.ocaml.org/u/perry)\
**Post date:** [May 4, 2018, 12:48pm UTC](https://discuss.ocaml.org/t/sum-type-constructor-declaration-subtlety-and-documentation-wanted/1898/22 "2018-05-04T12:48:10Z")

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> [@Yaron\_Minsky](#):
>
> RWO now has some coverage of this

FYI, for reasons I can’t explain, DNS will not currently resolve the [dev.realworldocaml.org](http://dev.realworldocaml.org) address. ☹

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**Author:** ![Yaron\_Minsky](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/yaron_minsky/32/11_2.png) [@Yaron\_Minsky](https://discuss.ocaml.org/u/Yaron_Minsky)\
**Post date:** [May 4, 2018, 2:12pm UTC](https://discuss.ocaml.org/t/sum-type-constructor-declaration-subtlety-and-documentation-wanted/1898/23 "2018-05-04T14:12:59Z")

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Odd. I can see it fine. @avsm has been doing some DNS migrations, so I’m sure that’s related.

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**Author:** ![perry](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/perry/32/518_2.png) [@perry](https://discuss.ocaml.org/u/perry)\
**Post date:** [May 4, 2018, 2:16pm UTC](https://discuss.ocaml.org/t/sum-type-constructor-declaration-subtlety-and-documentation-wanted/1898/24 "2018-05-04T14:16:34Z")

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The DNS now resolves okay.

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**Author:** ![avsm](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/avsm/32/6_2.png) [@avsm](https://discuss.ocaml.org/u/avsm)\
**Post date:** [May 8, 2018, 12:02pm UTC](https://discuss.ocaml.org/t/sum-type-constructor-declaration-subtlety-and-documentation-wanted/1898/25 "2018-05-08T12:02:43Z")

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> [@perry](#):
>
> FYI, for reasons I can’t explain, DNS will not currently resolve the [dev.realworldocaml.org](http://dev.realworldocaml.org) address. ☹

I’ve been doing some shuffling to move some of the infrastructure to GitHub Pages’ new Letsencrypt hosting. It should be stable now; please let me know if not.

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**Author:** ![perry](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/perry/32/518_2.png) [@perry](https://discuss.ocaml.org/u/perry)\
**Post date:** [May 8, 2018, 12:21pm UTC](https://discuss.ocaml.org/t/sum-type-constructor-declaration-subtlety-and-documentation-wanted/1898/26 "2018-05-08T12:21:35Z")

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BTW, I think opinions on phrasing this have stabilized enough that a pull request to the main documentation would probably be appropriate now. Anyone disagree?

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