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Update and rename squeal-presentation-2018-09-12.html to squeal-presentation-raveline.md
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<!DOCTYPE html>
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<html>
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<head>
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<title>Title</title>
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<meta charset="utf-8">
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<style>
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@import url(https://fonts.googleapis.com/css?family=PT+Sans+Narrow);
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@import url(https://fonts.googleapis.com/css?family=Montserrat:400,700,400italic);
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@import url(https://fonts.googleapis.com/css?family=Ubuntu+Mono:400,700,400italic);
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body { font-family: 'Montserrat'; }
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h1, h2, h3 {
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font-family: 'PT Sans Narrow';
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font-weight: normal;
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}
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.note {
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background-color: #ccc;
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padding: 1rem;
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border-radius: 4px;
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}
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.remark-code, .remark-inline-code { font-family: 'Ubuntu Mono'; }
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.signature {
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position: absolute;
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top: 1%;
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right: 1%;
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font-size:.6em;
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opacity: .5;
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}
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</style>
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</head>
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<body>
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<textarea id="source">
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class: center, middle
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count: false
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# Squeal
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_A bridge between SQL and Haskell_
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.signature[2018/09/12 - by @Raveline]
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by [@Raveline](https://github.com/raveline)
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---
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@ -62,9 +24,6 @@ Using `postgresql-simple` you have a typical "Trial, error, despair" workflow:
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---
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class: center, middle
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count: false
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![Can't take this anymore](http://gif.eraveline.eu/static/img/0x16e.gif)
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---
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@ -85,9 +44,6 @@ However, it's not an ORM. There's no caching, lazy loading - you retain control
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---
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class: center, middle
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count: false
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# Part I. Schema & migration
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---
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@ -107,16 +63,13 @@ type Schema = '[ "mp" ::: 'Table MemberOfParliament
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, "groupp" ::: 'Table ParliamentGroup ]
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```
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--
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---
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.note[*
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We need the `DataKinds` extension to be able to express heterogenous lists containing
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specific types like this one.
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> _note_ We need the `DataKinds` extension to be able to express heterogenous lists containing
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> specific types like this one.
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*
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You can perfectly call your table "group" and not "groupp" even though it is a
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keyword in SQL - Squeal queries will be properly escaped.
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]
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> You can perfectly call your table "group" and not "groupp" even though it is a
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> keyword in SQL - Squeal queries will be properly escaped.
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---
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@ -139,16 +92,12 @@ type ParliamentaryGroup =
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- Let's split constraints and column to study the syntax a bit more.
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--
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.note[*
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We are using `:::` and `:=>` to quickly express associations when writing
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our schema. We need the `TypeOperators` extension.]
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---
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class: center, middle
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count: false
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> _note_ We are using `:::` and `:=>` to quickly express associations when writing
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> our schema. We need the `TypeOperators` extension.]
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---
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![What does this means ?!](http://gif.eraveline.eu/static/img/0x27e.gif)
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@ -195,10 +144,10 @@ type MpCols =
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* the type (obviously).
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--
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---
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.note[*
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GHC is already helping. If I named the "mp_id" column differently, GHC would yell because I promised a primary key constraint on a column named `mp_id`, so there must be one.]
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> _note_ GHC is already helping. If I named the "mp_id" column differently,
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> GHC would yell because I promised a primary key constraint on a column named `mp_id`, so there must be one.]
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---
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@ -208,7 +157,7 @@ GHC is already helping. If I named the "mp_id" column differently, GHC would yel
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- But before we play with this schema, we need to implement it.
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--
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---
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```haskell
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setup :: Definition '[] Schema
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@ -240,15 +189,14 @@ setup =
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- You use `>>>` to compose table creation.
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- Note that the compiler will catch any mistype between Schema and
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definition; wrong nullability, wrong type, wrong name, etc.
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> _note_ The compiler will catch any mistype between Schema and
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> definition; wrong nullability, wrong type, wrong name, etc.
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--
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---
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.note[*
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You'll also need `OverloadedLabels`, for naming stuff.
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This is mostly to avoid having to write manual proxies all
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the time and for convenience.]
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> _note_ You'll also need `OverloadedLabels`, for naming stuff.
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> This is mostly to avoid having to write manual proxies all
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> the time and for convenience.
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---
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@ -283,8 +231,8 @@ tearDown :: Definition Schema '[]
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tearDown = dropTable #mp >>> dropTable #groupp
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```
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- Note that GHC will also detect the _proper_ order of what you typed in
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downgrade and upgrade should there be any conflict (with foreign keys).
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> _note_ GHC will also detect the _proper_ order of what you typed in
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> downgrade and upgrade should there be any conflict (with foreign keys).
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```haskell
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initDB :: Migration IO '[] Schema
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@ -314,16 +262,10 @@ main = do
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---
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class: center, middle
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count: false
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![That was easy](http://gif.eraveline.eu/static/img/0x47f.gif)
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---
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class: center, middle
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count: false
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# Part II. Insertions
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---
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@ -369,9 +311,8 @@ data MemberOfParliament =
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, lastName :: Text }
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```
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- You'll note that we didn't use anything from Squeal.
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- The model can be entirely separated from the persistence layer.
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> _note_ We didn't use anything from Squeal.
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> The model can be entirely separated from the persistence layer.
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---
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@ -386,7 +327,7 @@ type GroupInsertionParams = '[ 'NotNull 'PGuuid
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- Params are not named, but they are indexed. You just need nullability and type.
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--
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---
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```haskell
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groupInsertion :: Manipulation Schema GroupInsertionParams '[]
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@ -395,7 +336,7 @@ groupInsertion =
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:* Set (param @2) `as` #name )
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```
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--
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---
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- `TypeApplication` lets us use the index of parameters (counting from 1).
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@ -410,19 +351,19 @@ _Inserting a Member of Parliament_
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- We could create a naive query that takes MP uuid, first name, last name and group uuid...
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--
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---
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- But that's boring. So let's use the `INSERT INTO ... SELECT`.
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--
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---
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- We will build a query that will return as constants our MP's uuid, first name and last name...
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--
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---
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- ... and fetch the uuid of a group given the name of the group.
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--
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---
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- There's a `insertQuery` utility function for that. All we have to do is write the `select` !
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@ -572,16 +513,11 @@ insertParliament = traverse_ insertGroup
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---
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class: center, middle
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count: false
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![Very simple](https://media1.tenor.com/images/0188c63209aced59f1583e1ca94e509e/tenor.gif?itemid=3550689)
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---
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class: center, middle
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# Part III. Selects
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---
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@ -653,7 +589,7 @@ type BaseParliamentSelection =
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, "m" ::: TableToRow MpCols ]
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```
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- Note that we've also put everything with table aliases: "g" and "m".
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> _note_ We've also put everything with table aliases: "g" and "m".
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---
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@ -831,16 +767,10 @@ getGroupMembers =
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---
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class: center, middle
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count: false
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![Eazy](https://media.tenor.com/images/8fc7c4077efe11b4a3a3b9ae4e643e87/tenor.gif)
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---
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class: center, middle
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count: false
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# Conclusion
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---
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@ -860,17 +790,5 @@ count: false
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- Typesafe. 'nuff said.
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---
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class: center, middle
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count: false
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# Thank you !
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</textarea>
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<script src="https://remarkjs.com/downloads/remark-latest.min.js">
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</script>
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<script>
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var slideshow = remark.create({countIncrementalSlides: false});
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</script>
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||||
</body>
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</html>
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