# Reads for GADT, existential types, universally quantified type code

**URL:** https://discuss.ocaml.org/t/reads-for-gadt-existential-types-universally-quantified-type-code/5464
**Category:** Learning
**Tags:** gadt, existential-types
**Created:** [April 8, 2020, 12:04pm UTC](https://discuss.ocaml.org/t/reads-for-gadt-existential-types-universally-quantified-type-code/5464 "2020-04-08T12:04:21Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![milvi](https://avatars.discourse-cdn.com/v4/letter/m/9fc348/32.png) [@milvi](https://discuss.ocaml.org/u/milvi)
#### Post date: [April 8, 2020, 12:04pm UTC](https://discuss.ocaml.org/t/reads-for-gadt-existential-types-universally-quantified-type-code/5464/1 "2020-04-08T12:04:21Z")

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Hello 🙂

Do you know code with plenty of GADT, existential types, universally quantified types ?

I would like to read such things.

Thanks !

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### Author: ![arbipher](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/arbipher/32/3544_2.png) [@arbipher](https://discuss.ocaml.org/u/arbipher)
#### Post date: [April 8, 2020, 4:05pm UTC](https://discuss.ocaml.org/t/reads-for-gadt-existential-types-universally-quantified-type-code/5464/2 "2020-04-08T16:05:49Z")

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The _plenty_ makes me less confident on whether my reply is fine.

For gadt, you can click the gadt tag just below the post title to find all posts here on gadt.  
I read all of them when I learn the usage of gadt.

(In the post I forgot which) I found this collection of gadt from objmagic [https://github.com/objmagic/jaw](https://github.com/objmagic/jaw)

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### Author: ![milvi](https://avatars.discourse-cdn.com/v4/letter/m/9fc348/32.png) [@milvi](https://discuss.ocaml.org/u/milvi)
#### Post date: [April 9, 2020, 12:54am UTC](https://discuss.ocaml.org/t/reads-for-gadt-existential-types-universally-quantified-type-code/5464/3 "2020-04-09T00:54:14Z")

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hooohoh nice repo 🤩 !

Well, I am looking to packing a small literature. Anything goes : academic papers showing off these things (what they enable and their pitfalls/limitations), perls, puzzles, real life code.

[The manual](https://ocaml.org/releases/4.10/htmlman/polymorphism.html) has en entry on polymorphism tackling awkward type inference with _explicit universally quantified types_ and _explicit polymorphic annotations_

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### Author: ![grayswandyr](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/grayswandyr/32/94_2.png) [@grayswandyr](https://discuss.ocaml.org/u/grayswandyr)
#### Post date: [April 9, 2020, 7:49am UTC](https://discuss.ocaml.org/t/reads-for-gadt-existential-types-universally-quantified-type-code/5464/4 "2020-04-09T07:49:02Z")

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[Xavier Thirioux](http://thirioux.perso.enseeiht.fr/)’s [Habilitation thesis](http://thirioux.perso.enseeiht.fr/docs/hdr.pdf) contains a large development around Taylor series in OCaml using GADTs. I think it deserves to be better known.

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### Author: ![nico.d](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/nico.d/32/5865_2.png) [@nico.d](https://discuss.ocaml.org/u/nico.d)
#### Post date: [March 20, 2025, 7:39pm UTC](https://discuss.ocaml.org/t/reads-for-gadt-existential-types-universally-quantified-type-code/5464/5 "2025-03-20T19:39:15Z")

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Hello,

Thanks for the link, it is a really interesting repository, but the code itself is hard to understand without any comment. Do you know where can I find human readable explanation for all this ?

Note: I have already read the relevant chapter in OCaml manual and Real World OCaml.

Cheers,  
Nico