{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Variable Inspector Widget"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## A short example implementation"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This notebook demonstrates how one can use the widgets already built-in to IPython to create a working variable inspector much like the ones seen in popular commercial scientific computing environments."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "import ipywidgets as widgets # Loads the Widget framework.\n",
    "from IPython.core.magics.namespace import NamespaceMagics # Used to query namespace.\n",
    "\n",
    "# For this example, hide these names, just to avoid polluting the namespace further\n",
    "get_ipython().user_ns_hidden['widgets'] = widgets\n",
    "get_ipython().user_ns_hidden['NamespaceMagics'] = NamespaceMagics"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "class VariableInspectorWindow(object):\n",
    "    instance = None\n",
    "    \n",
    "    def __init__(self, ipython):\n",
    "        \"\"\"Public constructor.\"\"\"\n",
    "        if VariableInspectorWindow.instance is not None:\n",
    "            raise Exception(\"\"\"Only one instance of the Variable Inspector can exist at a \n",
    "                time.  Call close() on the active instance before creating a new instance.\n",
    "                If you have lost the handle to the active instance, you can re-obtain it\n",
    "                via `VariableInspectorWindow.instance`.\"\"\")\n",
    "        \n",
    "        VariableInspectorWindow.instance = self\n",
    "        self.closed = False\n",
    "        self.namespace = NamespaceMagics()\n",
    "        self.namespace.shell = ipython.kernel.shell\n",
    "        \n",
    "        self._box = widgets.Box()\n",
    "        self._box._dom_classes = ['inspector']\n",
    "        self._box.background_color = '#fff'\n",
    "        self._box.border_color = '#ccc'\n",
    "        self._box.border_width = 1\n",
    "        self._box.border_radius = 5\n",
    "\n",
    "        self._modal_body = widgets.VBox()\n",
    "        self._modal_body.overflow_y = 'scroll'\n",
    "\n",
    "        self._modal_body_label = widgets.HTML(value = 'Not hooked')\n",
    "        self._modal_body.children = [self._modal_body_label]\n",
    "\n",
    "        self._box.children = [\n",
    "            self._modal_body, \n",
    "        ]\n",
    "        \n",
    "        self._ipython = ipython\n",
    "        self._ipython.events.register('post_run_cell', self._fill)\n",
    "        \n",
    "    def close(self):\n",
    "        \"\"\"Close and remove hooks.\"\"\"\n",
    "        if not self.closed:\n",
    "            self._ipython.events.unregister('post_run_cell', self._fill)\n",
    "            self._box.close()\n",
    "            self.closed = True\n",
    "            VariableInspectorWindow.instance = None\n",
    "\n",
    "    def _fill(self):\n",
    "        \"\"\"Fill self with variable information.\"\"\"\n",
    "        values = self.namespace.who_ls()\n",
    "        self._modal_body_label.value = '<table class=\"table table-bordered table-striped\"><tr><th>Name</th><th>Type</th><th>Value</th></tr><tr><td>' + \\\n",
    "            '</td></tr><tr><td>'.join(['{0}</td><td>{1}</td><td>{2}'.format(v, type(eval(v)).__name__, str(eval(v))) for v in values]) + \\\n",
    "            '</td></tr></table>'\n",
    "\n",
    "    def _ipython_display_(self):\n",
    "        \"\"\"Called when display() or pyout is used to display the Variable \n",
    "        Inspector.\"\"\"\n",
    "        self._box._ipython_display_()\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "inspector = VariableInspectorWindow(get_ipython())\n",
    "inspector"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Pop the inspector out of the widget area using Javascript.  To close the inspector, click the close button on the widget area that it was spawned from."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "%%javascript\n",
    "$('div.inspector')\n",
    "    .detach()\n",
    "    .prependTo($('body'))\n",
    "    .css({\n",
    "        'z-index': 999, \n",
    "        position: 'fixed',\n",
    "        'box-shadow': '5px 5px 12px -3px black',\n",
    "        opacity: 0.9\n",
    "    })\n",
    "    .draggable();"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Test"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "a = 5"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "b = 3.0"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "c = a * b"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "d = \"String\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "del b"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "inspector.close()"
   ]
  }
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