rayshih

我就直接回在下面了

回應 https://gist.github.com/rayshih/4144d6b8bc045fc26daf8887bd0cb4e2。

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我一直覺得你的發言和其他人沒有交集，但想不通到底哪裡出了問題。但看了這段程式之後，我覺得有點懂了。原文的程式不容易看 timestamp（加上 1th 2th 3th 讓我豆頁痛），所以我稍微改寫如下。

import asyncio

rayshih

from datetime import datetime
import asyncio

# The code is based on this link:
# https://www.facebook.com/photo.php?fbid=1723296854349009&set=p.1723296854349009&type=3&theater
# And of course, the output is exactly the same.
# For conveniency, I attached the output at the end of this file.

# ----- begin of polyfill -----
Await = 'await'

rayshih

但只用純 Python 的 generator 沒辦法為 Python 的所有功能實作 async variant，因為這會有雞生蛋生雞問題。最簡單的矛盾：如果你只用 generator 實作 async API，那要怎麼實作 async 的 generator？

嗯？為什麼不行？

import asyncio
import time

def async_generator():
    @asyncio.coroutine

rayshih

Re: asyncio 好寫嗎？

首先，其實還滿開心有機會可以做個小小辯論的啦。我的回應如下

這把好幾個主題混在一起了，需要一個一個看。

1. Async Program 好寫嗎？

不好寫。東西好不好寫的意思，代表它和 programmer 的內在思考模式符合程度。Async program 不符合人類習慣思維，所以才會被說一開始的學習 overhead 很高，寫起來容易卡。尤其如果同步與異步 paradigms 並立（例如 Python），就更容易在切換的時候出問題。

rayshih

import express from 'express'
import {Observable} from 'rxjs'
import {pipe, append, map, reduce} from 'ramda'

// ----- begin of framework layer -----
// This bridges express framework into rx world

const toRoute$ = app => ([method, route, handler]) =>
  Observable.create(observer => {
    app[method](route, (req, res) => {

rayshih

data Program next = Output String next | Done

p = Output "Hello World" (Output "Good Bye" Done)

-- an interpreter to run
run :: Program (Program (Program next)) -> IO ()
run (Output s1 (Output s2 Done)) = do
  putStrLn s1
  putStrLn s2

rayshih

test header 1

test header 2

test header 3

test header 4

rayshih

// ----- start of "extracted functions" ------
const toggleLoggedActivity = (data) => {
  const selectedActivity = getActivity(activities, data.activityKey);
  const selectedActivitySubCategory = getSubCategory(activities, data.activityKey);
  const transactionCallback = toggleLoggedActivity(data, activities, selectedActivity, selectedActivitySubCategory);

  const loggedProfileRef = firebase.database()
    .ref(`loggedActivities/${data.datetime}/${data.profileUid}`);

  return utils.getValue(loggedProfileRef)

rayshih

Array.prototype.flatMap = function(f) {
  const r = []
  for (var i = 0; i < this.length; i++) {
    f(this[i]).forEach(v => {
      r.push(v)
    })
  }
  return r
}

rayshih

const createExecObj = exec => ({
  exec,
  bind(f) {
    return createExecObj(cb => {
      this.exec(y => {
        f(y).exec(cb)
      })
    })
  }
})