https://mybinder.org/v2/gist/tonyfast/a990c66c804e0dbed659b66d222aea87/master

awidgetable.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# awidgetable"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 82,
   "metadata": {},
   "outputs": [],
   "source": [
    "import ipywidgets as W, traitlets as T, IPython, random\n",
    "from asyncio.queues import Queue\n",
    "import asyncio"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "class WillHave(object):\n",
    "    _widget = None\n",
    "\n",
    "    def __init__(self, widget):\n",
    "        self._widget = widget\n",
    "\n",
    "    async def __get(self, value):\n",
    "        return await self._widget._queues[value][\"queue\"].get()\n",
    "    \n",
    "    def __getattr__(self, value):\n",
    "        return self.__get(value)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "class Awaitable(T.HasTraits):\n",
    "    _queues = T.Dict()\n",
    "    will_have = T.Instance(WillHave)\n",
    "    \n",
    "    @T.default(\"_queues\")\n",
    "    def _default_queues(self):\n",
    "        queues = {}\n",
    "        for trait in self.trait_names():\n",
    "            queues[trait] = self._enqueue_trait(trait)\n",
    "        return queues\n",
    "    \n",
    "    @T.default(\"will_have\")\n",
    "    def _default_will_have(self):\n",
    "        return WillHave(self)\n",
    "        \n",
    "    def _enqueue_trait(self, trait):\n",
    "        queue = Queue()\n",
    "\n",
    "        def _on_change(change):\n",
    "            # don't `put` if nobody's `get`ting\n",
    "            queue.empty() and queue.put_nowait({\"old\": change[\"old\"], \"new\": change[\"new\"]})\n",
    "        \n",
    "        self.observe(_on_change, trait)\n",
    "        return {\n",
    "            \"queue\": queue,\n",
    "            \"handler\": _on_change\n",
    "        }"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "class AwaitableFloatSlider(Awaitable, W.FloatSlider):\n",
    "    pass"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Some example code that might be awaiting."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 84,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "5ad2f895c5ff407db6f202e29a59f7f8",
       "version_major": 2,
       "version_minor": 0
      },
      "text/plain": [
       "AwaitableFloatSlider(value=0.0, layout=Layout(width='100%'))"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "try: del afs, printy\n",
    "except: pass\n",
    "afs = AwaitableFloatSlider(layout=dict(width=\"100%\"))\n",
    "display(afs)\n",
    "\n",
    "md = \"text/markdown\"\n",
    "\n",
    "max_dv = 0\n",
    "\n",
    "async def printy():\n",
    "    global max_dv\n",
    "    disp = IPython.display.display({md: \"> Move the slider quickly!\"}, raw=True, display_id=True)\n",
    "    while True:\n",
    "        c1 = await afs.will_have.value\n",
    "        c2 = await afs.will_have.value\n",
    "        dv = int(c2[\"new\"] - c1[\"old\"])\n",
    "        max_dv = max(max_dv, abs(dv))\n",
    "        tmp = \"# last speed `{}`\\n\\n> # {}\"\n",
    "        for i in range(10):\n",
    "            msg = tmp.format(dv, random.choice(\"⠺⠭⠽⠵\"))\n",
    "            disp.update({md: msg}, raw=True, update=True)\n",
    "            await asyncio.sleep(0.04 * i)\n",
    "        msg += f\"\\n# max speed `{max_dv}`\"\n",
    "        disp.update({md: msg}, raw=True, update=True)\n",
    "        \n",
    "        if abs(dv) == max_dv:\n",
    "            msg += \"\\n# Good Job!\"\n",
    "            disp.update({md: msg}, raw=True, update=True)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Queue it up."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 85,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/markdown": [
       "# last speed `75`\n",
       "\n",
       "> # ⠺\n",
       "# max speed `75`\n",
       "# Good Job!"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "asyncio.ensure_future(printy());"
   ]
  }
 ],
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  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
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  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
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 "nbformat": 4,
 "nbformat_minor": 4
}