pythonnet-formatter.ipynb

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   "cells": [
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "# python.net\n",
      "\n",
      "http://pythonnet.github.io/readme.html\n",
      "\n",
      "## Installation\n",
      "\n",
      "In order to use https://github.com/pythonnet/pythonnet in my virtualenvs and to run this notebook I had to run the following commands. I intentionally cloned and installed locally in dev mode.\n",
      "* sudo apt-get install mono-complete\n",
      "* mkvirtualenv bootstrap-npython\n",
      "* git clone https://github.com/pythonnet/pythonnet.git\n",
      "* cd pythonnet\n",
      "* sudo apt-get install libglib2.0-cil \n",
      "    * setup.py of pythonnet runs pkg-config on glib-2, which coulnd't be found, therefore I install gtksharp\n",
      "* pip install -e . \n",
      "* pip install ipython[notebook]\n",
      "\n",
      "I then bootstrapped a new virtualenv from this one with npython as the python interpreter. \n",
      "* which npython (on my machine it is $WORKON_HOME/bootstrap-python/bin/npython.exe)\n",
      "* mkvirtualenv npython -p <path to the npython.exe>\n",
      "\n",
      "Finally you are ready to launch ipython and all other modules, which are creating console scripts with npython as python executable to be able to _import clr_"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import clr\n",
      "import System\n",
      "from System import String, Int32, Environment\n",
      "from System.Collections.Generic import Dictionary\n",
      "from pprint import pprint"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "## Custom display formatter for .NET types\n",
      "\n",
      "IPython can register custom display formaters (like Debug Visualizers in Visual Studio) for types and therefore uses IPython.lib.pretty\n",
      "\n",
      "* https://github.com/ipython/ipython/blob/master/IPython/lib/pretty.py\n",
      "* http://ipython.org/ipython-doc/dev/api/generated/IPython.lib.pretty.html\n",
      "* https://github.com/ipython/ipython/blob/master/IPython/core/formatters.py\n",
      "* http://ipython.org/ipython-doc/dev/api/generated/IPython.core.formatters.html\n",
      "\n",
      "I had issues to get a matching condition on n.GetType().IsAssignableFrom(System.Collections.IDictionary) and other types. I guess it is the boxing or me not knowing how to pass the right type in. Therefore I use a duck typing approach to probe on the items for item.Key and item.Value. As all .NET types derive from System.Object I decided to register a single formatter for type System.Object\n",
      "\n",
      "**TODO:** Package formatter as an extension"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "formatter = get_ipython().display_formatter.formatters['text/plain']\n",
      "\n",
      "def format_dotnet(n, p, cycle):\n",
      "    my_type = n.GetType()\n",
      "    try:\n",
      "        dict_like = {i.Key: i.Value for i in n}\n",
      "    except:\n",
      "        dict_like = None\n",
      "    \n",
      "    def format_iter(iterable, format_item):\n",
      "        if cycle:\n",
      "            p.text('{}(...)'.format(my_type))\n",
      "        else:\n",
      "            p.begin_group(4, '{}(['.format(my_type))\n",
      "            p.breakable()\n",
      "            for idx, item in enumerate(iterable):\n",
      "                if idx:\n",
      "                    p.text(',')\n",
      "                    p.breakable()\n",
      "                format_item(item, p)\n",
      "            p.end_group(4, '])')\n",
      "            \n",
      "    if dict_like:\n",
      "        def format_dict_item(item, p):\n",
      "            p.pretty(\"{}: \".format(item[0]))\n",
      "            p.pretty(item[1])\n",
      "        format_iter(dict_like.iteritems(), format_dict_item)\n",
      "    elif my_type.IsArray:\n",
      "        format_iter(n, lambda item: item)\n",
      "    else:\n",
      "        p.text(n.ToString())\n",
      "formatter.for_type(System.Object, format_dotnet)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 2
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "dict1 = Dictionary[String, String]()\n",
      "dict2 = Dictionary[String, Int32]()\n",
      "dict1[\"test\"] = \"hallo\"\n",
      "dict1[\"test2\"] = \"welt\"\n",
      "dict2[\"test\"] = 1\n",
      "dict2[\"test2\"] = 2"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 3
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "dict1"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 4,
       "text": [
        "System.Collections.Generic.Dictionary`2[System.String,System.String]([\n",
        "    'test: 'u'hallo',\n",
        "    'test2: 'u'welt'])"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "dict2"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 5,
       "text": [
        "System.Collections.Generic.Dictionary`2[System.String,System.Int32]([\n",
        "    'test: '1,\n",
        "    'test2: '2])"
       ]
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "code",
     "collapsed": true,
     "input": [
      "if Environment.OSVersion.VersionString.lower().startswith(\"unix\"):\n",
      "    release = !cat /etc/*release\n",
      "    release.append(('KERNEL={}'.format(Environment.OSVersion.Version)))\n",
      "    pprint(release)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "['DISTRIB_ID=Ubuntu',\n",
        " 'DISTRIB_RELEASE=14.04',\n",
        " 'DISTRIB_CODENAME=trusty',\n",
        " 'DISTRIB_DESCRIPTION=\"Ubuntu 14.04 LTS\"',\n",
        " 'NAME=\"Ubuntu\"',\n",
        " 'VERSION=\"14.04, Trusty Tahr\"',\n",
        " 'ID=ubuntu',\n",
        " 'ID_LIKE=debian',\n",
        " 'PRETTY_NAME=\"Ubuntu 14.04 LTS\"',\n",
        " 'VERSION_ID=\"14.04\"',\n",
        " 'HOME_URL=\"http://www.ubuntu.com/\"',\n",
        " 'SUPPORT_URL=\"http://help.ubuntu.com/\"',\n",
        " 'BUG_REPORT_URL=\"http://bugs.launchpad.net/ubuntu/\"',\n",
        " 'KERNEL=3.13.0.29']\n"
       ]
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "get_ipython().display_formatter.active_types"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 7,
       "text": [
        "[u'text/plain',\n",
        " u'image/jpeg',\n",
        " u'text/html',\n",
        " u'image/svg+xml',\n",
        " u'image/png',\n",
        " u'application/javascript',\n",
        " u'text/markdown',\n",
        " u'text/latex',\n",
        " u'application/json',\n",
        " u'application/pdf']"
       ]
      }
     ],
     "prompt_number": 7
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "Environment.OSVersion"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 8,
       "text": [
        "Unix 3.13.0.29"
       ]
      }
     ],
     "prompt_number": 8
    }
   ],
   "metadata": {}
  }
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}