dyokomizo

                <DT><H3 ADD_DATE="1390495188" LAST_MODIFIED="1411568985">formats</H3>
                <DL><p>
                    <DT><A HREF="http://swannodette.github.io/2014/07/23/a-closer-look-at-transit/" ADD_DATE="1406235975">A Closer Look at Transit</A>
                    <DT><A HREF="http://ocharles.org.uk/blog/posts/2014-06-10-reversible-serialization.html" ADD_DATE="1403296256">A Category for Correct-By-Construction Serializers and Deserializers</A>
                    <DT><A HREF="http://tools.ietf.org/html/draft-alakuijala-brotli-01" ADD_DATE="1402837786" ICON="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAl0lEQVQ4jaVSwRHEIAhcb64jUpPWRGqCmrhHlJMkPhJ2xoFZdIXVYmaGBD6ZwwDwHYm2LRSI5cIBAFUGiP6ETZBKJpVsyYkcuYjXn43Qb9a9OZX24JmA6tFIZafKeMa3JrrAW6Q9KFIp1UF+hGHUHMdyvrsPVZz3XzwglhCB/nFUwwfyDma1FYgFurcgGgTuCqvOZmjb8ANXSXxE46FkwQAAAABJRU5ErkJggg==">draft-alakuijala-brotli-01 - Brotli Compressed Data Format</A>
                    <DT><A HREF="https://github.com/JonathanSalwan/binary-sa

dyokomizo

module Fix where

left :: a -> (a -> c) -> (b -> c) -> c
left a l r = l a 

right :: b -> (a -> c) -> (b -> c) -> c
right b l r = r b

fix f a = f a (fix f) id

dyokomizo

We have three data types:

 - Name and Password, both with String representations;
 - Account, a Name and Password pair.

Given that each data type can have its invariants, we have some functions, representing morphisms from the data type to its representation (M is some Monad, like Maybe/Either/Validation, it's not important which):

 - stringToName :: String -> M Name
 - nameToString :: Name -> String

dyokomizo

Original link: http://www.concentric.net/~Ttwang/tech/inthash.htm
Taken from: http://web.archive.org/web/20071223173210/http://www.concentric.net/~Ttwang/tech/inthash.htm
Reformatted using pandoc

Integer Hash Function

Thomas Wang, Jan 1997

last update Mar 2007

dyokomizo

# Bottom-up Type Annotation with the Cofree Comonad

How do we add extra information to a tree? This has been called [The
AST Typing
Problem](http://blog.ezyang.com/2013/05/the-ast-typing-problem/).

After being hit with this problem in Roy's new type-inference engine,
I tried figuring out how to represent the algorithm. I eventually
realised that it looked like a comonadic operation. Turns out it's
been done before but I couldn't find any complete example.

dyokomizo

{-# LANGUAGE EmptyDataDecls, GADTs #-}

module Glob where
  
data L -- Witness for globs that begin/end with a literal
data S -- Witness for globs that begin/end with a star

data Glob a b e where -- Globs over [a] that begin with b and end with e
    L    :: [a]  -> Glob a L L                      -- Literal glob
    S    :: Glob a S S                              -- Star glob

dyokomizo

-- Inspired by http://www2.tcs.ifi.lmu.de/~abel/popl13.pdf

[codata|
  codata Stream a where
    head :: Stream a -> a
    tail :: Stream a -> Stream a
|]

fib :: Stream Nat
[copattern|

dyokomizo

{-# LANGUAGE NoImplicitPrelude, MultiParamTypeClasses, Rank2Types, TypeOperators #-}

newtype Id a =
  Id a

data a :\/ b =
  Left a
  | Right b

data a :/\ b =

dyokomizo

{-# LANGUAGE GADTs, KindSignatures #-}
module FakeWebFramework (add , notActuallyAWebFramework, get, Handler', link) where

import UrlPath
import Control.Monad.Writer 
import Data.Maybe

maybeRead :: (Read a) => String -> Maybe a
maybeRead s = case reads s of
  [(x, "")] -> Just x

dyokomizo

Latency Comparison Numbers
--------------------------
L1 cache reference                            0.5 ns
Branch mispredict                             5   ns
L2 cache reference                            7   ns             14x L1 cache
Mutex lock/unlock                            25   ns
Main memory reference                       100   ns             20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy              3,000   ns
Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
Read 4K randomly from SSD*              150,000   ns    0.15 ms