0X0xmohit·Oct 6, 2016
Link to slides: https://github.com/meiersi/HaskellerZ/blob/a19f6c28cd999efda...
In Haskell: mistakes I made (and how to fix them)zfoh
HaskellerZ
HTML2013–2016
zfoh / HaskellerZ
HaskellerZ
Notes and files from HaskellerZ meetups.
4Distinct people
4Mentions
0Explicit recommenders
215GitHub stars
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Notes and files from HaskellerZ meetups.
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Observed mentions: 2013-08-30 11:56:18 UTC to 2016-10-06 08:24:09 UTC.
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| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2013 | 2013-01-01 00:00:00 UTC | 2014-01-01 00:00:00 UTC | 1 | 1 | 0 |
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 1 | 0 | 1 |
What Hacker News says
4 sourcesSlides from Marlow from 9 months ago about Haxl and it's workings https://github.com/meiersi/HaskellerZ/blob/master/meetups/20...
In Facebook open sources HaxlI'm sorry if I wasn't clear. With the appropriate types in Haskell, you can write a data type that would be called a free applicative functor. It can be used to describe the shape of a computation. By reducing the surface area of said functor, by not exposing the "pure" operation, one can describe computation that are fixed in terms of their input.
This is amazing, because I mean truly fixed. The course of execution cannot be altered by the values of the input. Cache line eviction? All memory access is statically known in advance. Branch prediction? There are no branches.
The code would look a lot like what the Haxl[1] project at Facebook has produced. They used applicative functors to create a domain-specific language that described the shape of a computation without specifying the details. That allows them to write a compiler for their
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DSL in Haskell. In their case, they used Haxl to hide concurrency from their users, Facebook developers. Those developers can use Haxl to write concurrent, cached, optimized and type-checked queries against Facebook's datastores, without having to know how to write safe concurrent, fast queries. To the Facebook developers, there is no concurrency, the code they write just looks like a monad or an applicative in Haskell.
It should be no surprise then that one of the lead developers of Haxl originally worked on the Glasgow Haskell Compiler.
[1] Haxl slides [PDF warning]: https://github.com/meiersi/HaskellerZ/raw/master/meetups/201...
The Haxl Project at Facebook [pdf]
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