Untitled.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "from jupyterlab_omnisci.altair import extract_spec, EMPTY_SPEC"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "res = None\n",
    "\n",
    "def callback(data):\n",
    "    global res\n",
    "    res = data\n",
    "\n",
    "extract_spec(EMPTY_SPEC, callback)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'data': {'values': []}, 'mark': 'bar'}"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "res"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Now let's try with asyncio, by creating a future around the callback:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "import asyncio"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [],
   "source": [
    "res_future = asyncio.Future()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<Future pending>"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def callback(data):\n",
    "    res_future.set_result(data)\n",
    "\n",
    "extract_spec(EMPTY_SPEC, callback)\n",
    "res_future"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'data': {'values': []}, 'mark': 'bar'}"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "await res_future"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Now let's try it but await for the future:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [],
   "source": [
    "res_future_2 = asyncio.Future()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "ename": "CancelledError",
     "evalue": "",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mCancelledError\u001b[0m                            Traceback (most recent call last)",
      "\u001b[0;32mcell_name\u001b[0m in \u001b[0;36masync-def-wrapper\u001b[0;34m()\u001b[0m\n",
      "\u001b[0;31mCancelledError\u001b[0m: "
     ]
    }
   ],
   "source": [
    "\n",
    "def callback(data):\n",
    "    res_future_2.set_result(data)\n",
    "\n",
    "extract_spec(EMPTY_SPEC, callback)\n",
    "await res_future_2"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This will never finish"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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