techtangents

Install "Simple Theme Plugin" - this gives you some theme settings

Configure System > URL of theme CSS = /userContent/noBreadcrumbPopups.css

This maps to something like /var/lib/jenkins/home/userContent/noBreadcrumbPopups.css

Create this file with contents:

#breadcrumb-menu, #breadcrumb-menu * {
  display: none !important;

techtangents

Let's use Scala as the implementation language. 
Say you have an API function setFoo, that is overloaded for Chook and Dog. 
One might call it either of these ways:

setFoo(chook)
setFoo(dog)

As an API user, I wish to call this function from another function

def q(c: Chook) {

techtangents

Simon Peyton-Jones
Phillip Wadler
Paul Chiusano
Tony Morris
Mark Hibberd
Edwin Brady
John Carmack
Conor McBride
Evan Czaplicki
Brian McKenna

techtangents

  /** applyF :: ((a -> b), a) -> b */
	public static <A, B> F2<F<A, B>, A, B> applyF() {
		return new F2<F<A, B>, A, B>() {
			@Override
			public B apply(final F<A, B> f, final A a) {
				return f.apply(a);
			}
		};
	}

techtangents

There seems to be a lot of confusion around Effects and IO. I wanted to collect a set of questions and answers, and explanations of common misconceptions.

1. What is an Effect?
2. What is a Side Effect?
3. What is a pure function?
4. What is equational reasoning?
5. What is an IO?
6. Is the purpose IO value used to model an effectful computation, such that it can be composed with other computations?
7. Is Haskell's unsafePerformIO an impure function?
8. Related: Is it true that forall a, IO a is

techtangents

data Effect = Effect {
  unsafePerform :: ()
}

data Effect1 a = Effect1 {
  unsafePerform1 :: a -> ()
}

effectToEffect1 :: Effect -> Effect1 a
--effectToEffect1 fx = Effect1 (\_ -> unsafePerform fx)

techtangents

{-

bryanwoods: Haskell folk: Any way to type a function like
generateEvens = [x | x <- [1..], x `mod` 2 == 0]
such that it always returns even numbers?

pedrofurla: @bryanwoods @puffnfresh in ghci `let generateEvens = ...` compiled just fine here

bryanwoods: @pedrofurla I was wondering if I could write a type signature like: generateEvens :: [EvenNumber]

techtangents

import Control.Applicative

isA :: a -> Bool
isA = undefined

isB :: a -> Bool
isB = undefined

isC :: a -> Bool
isC = undefined

techtangents

import Data.Semigroup
import Data.List.NonEmpty

isA :: a -> Bool
isA = undefined

isB :: a -> Bool
isB = undefined

isC :: a -> Bool

techtangents

import Data.Semigroup
import Data.List.NonEmpty

isA :: a -> Bool
isA = undefined

isB :: a -> Bool
isB = undefined

isC :: a -> Bool