fukaoi

abstract class Parent #同じシグネチャなので、abstractを通して、制約をつける
  abstract def disp
end

class A < Parent
  def disp : String
    "call A"
  end
end

fukaoi

class A
  def disp : String
    "call A"
  end
end

class B
  def disp : String
    "call B"
  end

fukaoi

### これだとMacro？生成ができないのか、 ``` undefined constant Crystal::Env```
### [NG]

require "env" 


### 代替手段
### [OK]

require "env/core"

fukaoi

module Demo
  STRUCT = [
    Bool, Char, Symbol,
    Int8, Int16, Int32, Int64, Int128,
    Float32, Float64
  ]

  macro define_struct
    {% for s in STRUCT %}
      struct {{ s.id }}

fukaoi

## default

>electrum-ltc create --testnet -w ~/Desktop/wallet
<<Password (hit return if you do not wish to encrypt your wallet):
>>test
<<Confirm:
>>test

## set env parameter

fukaoi

docker run -d  -p 5432:5432 -v /var/run/postgresql/:/var/run/postgresql/ --name mypost postgres

fukaoi

Keybase proof

I hereby claim:

• I am fukaoi on github.
• I am fukaoi (https://keybase.io/fukaoi) on keybase.
• I have a public key ASCUo-T8fcPOYbwnpufKBq85MsJs_sMYCq8i3C1Hxx-h3Qo

To claim this, I am signing this object:

fukaoi

class String
  def unpack(format : String) : Array
    io = IO::Memory.new(self)
    slice = Bytes.new(self.size)
    io.read(slice)
    [slice.hexstring]
  end
end

class Array

fukaoi

const exec = require('child_process').exec;

var obj = {
    "name":"太郎",
    "age": 30,
    "area":"Tokyo"
}
 
const json = JSON.stringify(JSON.stringify( obj ));
console.log(json)

fukaoi

require "io"
require "json"

io = IO::Memory.new
Process.run("cat ~/Work/hogepipe", shell: true, output: io)
p data = io.to_s.chomp
p JSON.parse(data)["name"]