dis.ipynb

{
 "metadata": {
  "name": ""
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import dis\n",
      "\n",
      "foo = [1]\n",
      "\n",
      "def bar(thing):\n",
      "    foo.append(thing)\n",
      "\n",
      "def baz(thing):\n",
      "    foo += thing\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "bar(2)\n",
      "bar(3)\n",
      "print foo"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "[1, 2, 3]\n"
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "baz('crap')"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "ename": "UnboundLocalError",
       "evalue": "local variable 'foo' referenced before assignment",
       "output_type": "pyerr",
       "traceback": [
        "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mUnboundLocalError\u001b[0m                         Traceback (most recent call last)",
        "\u001b[1;32m<ipython-input-4-c100cede7033>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mbaz\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m'crap'\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
        "\u001b[1;32m<ipython-input-1-ffa6c9e26809>\u001b[0m in \u001b[0;36mbaz\u001b[1;34m(thing)\u001b[0m\n\u001b[0;32m      7\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      8\u001b[0m \u001b[1;32mdef\u001b[0m \u001b[0mbaz\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mthing\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 9\u001b[1;33m     \u001b[0mfoo\u001b[0m \u001b[1;33m+=\u001b[0m \u001b[0mthing\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
        "\u001b[1;31mUnboundLocalError\u001b[0m: local variable 'foo' referenced before assignment"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "dis.dis(bar)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "  6           0 LOAD_GLOBAL              0 (foo)\n",
        "              3 LOAD_ATTR                1 (append)\n",
        "              6 LOAD_FAST                0 (thing)\n",
        "              9 CALL_FUNCTION            1\n",
        "             12 POP_TOP             \n",
        "             13 LOAD_CONST               0 (None)\n",
        "             16 RETURN_VALUE        \n"
       ]
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "dis.dis(baz)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "  9           0 LOAD_FAST                1 (foo)\n",
        "              3 LOAD_FAST                0 (thing)\n",
        "              6 INPLACE_ADD         \n",
        "              7 STORE_FAST               1 (foo)\n",
        "             10 LOAD_CONST               0 (None)\n",
        "             13 RETURN_VALUE        \n"
       ]
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def baz_plus(thing):\n",
      "    global foo\n",
      "    foo += thing"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 7
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "baz_plus('crap')\n",
      "print foo"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "[1, 2, 3, 'c', 'r', 'a', 'p']\n"
       ]
      }
     ],
     "prompt_number": 8
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "dis.dis(baz_plus)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "  3           0 LOAD_GLOBAL              0 (foo)\n",
        "              3 LOAD_FAST                0 (thing)\n",
        "              6 INPLACE_ADD         \n",
        "              7 STORE_GLOBAL             0 (foo)\n",
        "             10 LOAD_CONST               0 (None)\n",
        "             13 RETURN_VALUE        \n"
       ]
      }
     ],
     "prompt_number": 9
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [],
     "language": "python",
     "metadata": {},
     "outputs": []
    }
   ],
   "metadata": {}
  }
 ]
}