Creating a custom magic commands.ipynb

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   "cell_type": "markdown",
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   "source": [
    "## Creating a custom magic command in an IPython extension"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "from IPython.core.magic import register_cell_magic"
   ]
  },
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   "cell_type": "code",
   "execution_count": 2,
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    "collapsed": true
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    "@register_cell_magic\n",
    "def cpp(line, cell):\n",
    "    \"\"\"Compile, execute C++ code, and return the standard output.\"\"\"\n",
    "\n",
    "    # We first retrieve the current IPython interpreter instance.\n",
    "    ip = get_ipython()\n",
    "\n",
    "    # We define the source and executable filenames.\n",
    "    source_filename = '_temp.cpp'\n",
    "    program_filename = '_temp'\n",
    "\n",
    "    # We write the code to the C++ file.\n",
    "    with open(source_filename, 'w') as f:\n",
    "        f.write(cell)\n",
    "\n",
    "    # We compile the C++ code into an executable.\n",
    "    compile = ip.getoutput(\"g++ {0:s} -o {1:s}\".format(\n",
    "        source_filename, program_filename))\n",
    "\n",
    "    # We execute the executable and return the output.\n",
    "    output = ip.getoutput('./{0:s}'.format(program_filename))\n",
    "\n",
    "    print('\\n'.join(output))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Hello world!"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "%%cpp\n",
    "#include<iostream>\n",
    "int main()\n",
    "{\n",
    "    std::cout << \"Hello world!\";\n",
    "}"
   ]
  }
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