ChrisPenner

#!/bin/bash

if [[ $# -ne 2 ]]; then
    cat >&2 <<EOF
Transplant a branch from one root to another.
Handy if you've done a squash-merge and need to rebase <from> the old branch <onto> the new master.
Usage:
    git transplant <from> <to>

where:

ChrisPenner

#!/bin/bash

capdir=/tmp/cap
mkdir -p "$capdir"

record() {
    tee "${capdir}/${1:-default}"
}

replay() {

ChrisPenner

#!/bin/bash
# Use at your own risk :P
FOLDER="/tmp/copy-pasta"
if [ $# -lt 1 ]; then
    cat << EOF
usage: copy <files>
EOF
    exit 1
fi

ChrisPenner

{-# LANGUAGE OverloadedStrings #-}
module TextSpan where

import Control.Lens
import qualified Data.Text as T
import Text.RawString.QQ (r)
import qualified Data.List as List

type Line = Int
type Col = Int

ChrisPenner

module Folds.Filtering where

import Control.Lens

data Card =
    Card { _name    :: String
         , _aura    :: Aura
         , _holo    :: Bool -- Is the card holographic
         , _moves   :: [Move]
         } deriving (Show, Eq)

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

ChrisPenner

import Control.Lens
import Data.Typeable
import Data.Dynamic

dynamicLens :: Typeable a => (Lens' s a) -> Lens' s Dynamic
dynamicLens l = lens getter setter
  where
    getter s = toDyn $ view l s
    setter s b =
        case fromDynamic b of

ChrisPenner

You can use *most* optics as though they're a custom `traverse`

>>> (each . _Right) print (Left 1, Right 2, Left 3)
2
-- We can ignore the new structure it returns
(Left 1,Right (),Left 3)

It works on other types of effects too!
Here we use lists as a non-determinism effect to get all possible combos!

ChrisPenner

module Lib where

import Control.Comonad.Cofree
import Control.Monad.Reader
import Control.Concurrent

drawBar :: Float -> IO ()
drawBar n = putStrLn (replicate (ceiling n) '#')

type Animation = Cofree (Reader Float) Float

ChrisPenner

*Infix* typed holes!

>>> "suggest" `_` "concat" :: String

<interactive>:1:11: error:
    • Found hole: _ :: [Char] -> [Char] -> String
      Valid hole fits include
        showString :: String -> ShowS
        (++) :: forall a. [a] -> [a] -> [a]
        showList :: forall a. Show a => [a] -> ShowS