luochen1990

import java.util.function.Function;

public class EitherExample {
    public static void main(String[] args) {
        Either<String, Integer> x = new Left<>("hello");
        Either<String, Integer> y = new Right<>(123);
        System.out.println("hello");
        System.out.println(x);
        System.out.println(y);
    }

luochen1990

Task parameters:

/icon "c:\dev\msys2\msys2.ico" /dir "%CMDER_START%"

Command:

set CHERE_INVOKING=1 & set MSYS2_PATH_TYPE=inherit & %ConEmuDrive%\dev\msys2\usr\bin\bash.exe --login -i -new_console:t:"bash"

References:

luochen1990

docker_exec() {
  matches=$( docker ps | grep $1 )
  echo "$matches"
  pid=$(echo $matches | awk "{print \$1}" )
  echo Entering: $pid
  docker exec -it $pid sh
}

alias dx="docker_exec"

luochen1990

The mklink command is available on Windows Vista / Windows 7 / 2008 or later. And only Administrator can execute this command.

Suppose we have file a.txt, and now we need to create symbolic link b.txt:

mklink b.txt a.txt

This is similar to the following command in Linux:

luochen1990

--  | This is a module to explain the Attribute based access control system
--  , [ABAC](https://en.wikipedia.org/wiki/Attribute-based_access_control)
--  , [XACML](https://en.wikipedia.org/wiki/XACML)
module SimpleABAC where

import Data.Foldable

type AccessorAttr = String
type ResourceAttr = String
type OperationAttr = String

luochen1990

[[ -e ~/.profile ]] && emulate sh -c 'source ~/.profile'
[[ -e ~/.shrc ]] && emulate sh -c 'source ~/.shrc'
source $HOME/.antigen.zsh

# POWERLEVEL9K_INSTALLATION_PATH=$ANTIGEN_BUNDLES/bhilburn/powerlevel9k

antigen use oh-my-zsh

antigen bundles <<EOF
	npm

luochen1990

GET WAN IP Address

> nslookup myip.opendns.com. resolver1.opendns.com

...
Name: myip.opendns.com
Address: 101.69.24.2

luochen1990

Data.Foldable

• foldr1
• foldl1
• maximum
• minimum
• maximumBy
• minimumBy

Data.List

• head

luochen1990

import GHC.Stack

-- | a wrapper function to make "last" from base traceable
last' :: HasCallStack => [a] -> a
last' xs = case xs of [] -> error "abuse last"; _ -> last xs

-- | a untraceable partial function
foo :: [Int] -> Int
foo xs = last' xs + 1

luochen1990

The Concept of Totality

See the definition of partial function in wikipedia

Total Function & Partial Function

examples of total functions: