chrisdone

Typing Haskell in Haskell

MARK P. JONES

Pacific Software Research Center

Department of Computer Science and Engineering

Oregon Graduate Institute of Science and Technology

itod

• Kinesis Freestyle (Terrible key switches. Mushy and un-lovable)

• Kinesis Freestyle Edge (Traditional layout with too many keys, mech switches, proably too big to be tented easily/properly)

• Matias Ergo Pro (Looks pretty great. Have not tried.)

• ErgoDox Kit (Currently, my everyday keyboard. Can buy pre-assembled on eBay.)

• ErgoDox EZ (Prolly the best option for most people.)

leighman

module Main where

import Prelude
import Control.Monad.Eff (Eff)
import Control.Monad.Eff.Console (CONSOLE, logShow)
import Data.Either (Either(..))
import Data.Foldable (elem, notElem)
import Data.Int (toNumber)
import Data.Traversable (traverse)
import Data.Validation.Semigroup (invalid)

ahmetb

#!/bin/bash

# Copyright © 2017 Google Inc.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software

unya

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: example
spec:
  replicas: 2
  selector:
    matchLabels:
      app: example

i-am-tom

module Main where

-- | JSON is an incredibly simple format. Even its lists are untyped.
-- | As with all languages, functional programming encourages us to
-- | make a domain-specific language (or DSL) to capture the "ideas"
-- | of the language, which we can then use to talk about its content.

-- | In this little snippet, we'll build a JSON DSL, transform it into
-- | a recursive structure, and then use that result to generate some

garyb

-- | Binary operation
class Magma a where
  op ∷ a → a → a

-- | Associativity: `∀ a b. (a • b) • c = a • (b • c)`
class Magma a ⇐ Associative a

-- | Identity: `∀ a. a • identity = a && identity • a = a`
class Magma a ⇐ Identity a where
  identity ∷ a

i-am-tom

"For services to the PureScript Community, Gary Burgess!"

You've done it, Gary. Moore, Lineker, Coleman, and now Burgess. All the work was worth it. The halls erupted with praise. Children dressed as Space Ghost, teens with "I only get high on Halogen" t-shirts, a giant banner held aloft with the message, "Tuple @garyb me". Through the noise of the crowds and Phil's uninterpretable Northern accent, he barely managed to hear his theme tu-

BZZP. BZZP.

MonoidMusician

module Main where

import Type.Prelude
import Type.Row
import Type.Data.Boolean
import Type.Data.Symbol as Symbol
import Data.Newtype

data RProxy (r :: # Type) = RProxy
data RLProxy (rl :: RowList) = RLProxy

parsonsmatt

The question of "How do I design my application in Haskell?" comes up a lot. There's a bunch of perspectives and choices, so it makes sense that it's difficult to choose just one. Do I use plain monad transformers, mtl, just pass the parameters manually and use IO for everything, the ReaderT design pattern, free monads, freer monads, some other kind of algebraic effect system?!

The answer is: why not both/all?

Lately, I've been centering on a n application design architecture with roughly three layers:

Layer 1:

newtype AppT m a = AppT { unAppT :: ReaderT YourStuff m a } deriving ............ The ReaderT Design Pattern, essentially. This is what everything gets boiled down to, and what everything eventually gets interpreted in. This type is the backbone of your app. For some components, you carry around some info/state (consider [MonadMetrics](https://hackage