ChrisPenner

Optics By Example Cheat Sheets

The following are appendices from Optics By Example, a comprehensive guide to optics from beginner to advanced! If you like the content below, there's plenty more where that came from; pick up the book!

• Operators
• Composition Guide
• Substitution Guide
• Optical Constarints and Types

Operator Cheat Sheet

mikehaertl

Learn you a Haskell - In a nutshell

This is a summary of the "Learn You A Haskell" online book under http://learnyouahaskell.com/chapters.

---

1. Introduction

• Haskell is a functional programming language.

sdiehl

import Control.Monad

-------------------------------------------------------------------------------
-- State Monad Implementation
-------------------------------------------------------------------------------

newtype State s a = State { runState :: s -> (a,s) }

instance Monad (State s) where
  return a = State $ \s -> (a, s)

btroncone

RxJS 5 Operators By Example

⚠️ UPDATE: I have moved the contents of this gist plus more to http://www.learnrxjs.io and https://github.com/btroncone/learn-rxjs. For expanded examples, explanations, and resources, please check out this new location!

A complete list of RxJS 5 operators with easy to understand explanations and runnable examples.

Table of Contents

• buffer
• bufferCount
• bufferTime

bvaughn

React lifecycle cheatsheet

Method	Side effects1	State updates2	Example uses
Mounting
componentWillMount		✓	Constructor equivalent for createClass
render			Create and return element(s)
componentDidMount	✓	✓	DOM manipulations, network requests, etc.
Updating
componentWillReceiveProps		✓	Update state based on changed props

phadej

module SystemF where

open import Agda.Primitive
open import Prelude
open import Data.List

weaken-∈ : ∀ {a : Set} (Γ₁ : List a) {Γ x y} → x ∈ (Γ₁ ++ Γ) → x ∈ (Γ₁ ++ y ∷ Γ)
weaken-∈ [] (zero refl) = suc (zero refl)
weaken-∈ [] (suc i) = suc (suc i)
weaken-∈ (x ∷ Γ₁) (zero p) = zero p

phadej

module STLC where

open import Prelude
open import Data.List

infixr 7 _=>_
data Type : Set where
  nat : Type
  _=>_ : (a b : Type) → Type