decorator メモ

0_summary.md

• decoratorの復習
• wrapsってなに？
• その効果

mywrap.ipynb

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   "source": [
    "import mywraps"
   ]
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   "outputs": [
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     "text": [
      "decorated func nowarps\n",
      "example1\n"
     ]
    }
   ],
   "source": [
    "mywraps.example1()"
   ]
  },
  {
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   "outputs": [
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     "text": [
      "decorated fun wraps\n",
      "ex2\n"
     ]
    }
   ],
   "source": [
    "mywraps.example2()"
   ]
  },
  {
   "cell_type": "code",
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   "outputs": [
    {
     "name": "stdout",
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     "text": [
      "decorated func nowarps\n",
      "1 y2\n"
     ]
    }
   ],
   "source": [
    "func = lambda x, y=\"y1\": print(x, y)\n",
    "mywraps.decorator_nowraps(func)(1, y=\"y2\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "attrs = [\n",
    "    '__module__',\n",
    "    '__annotations__',\n",
    "    '__name__',\n",
    "    '__doc__',\n",
    "    '__dict__',\n",
    "]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "from pprint import pprint\n",
    "def print_attrs(attrs, obj):\n",
    "    pprint({attr: getattr(obj, attr, \"not exist\") for attr in attrs})"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'__annotations__': {},\n",
      " '__dict__': {},\n",
      " '__doc__': None,\n",
      " '__module__': 'mywraps',\n",
      " '__name__': 'wrapper'}\n"
     ]
    }
   ],
   "source": [
    "print_attrs(attrs, mywraps.example1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'__annotations__': {},\n",
      " '__dict__': {'__wrapped__': <function example2 at 0x00000000044CA8C8>},\n",
      " '__doc__': 'Docstr ex2',\n",
      " '__module__': 'mywraps',\n",
      " '__name__': 'example2'}\n"
     ]
    }
   ],
   "source": [
    "print_attrs(attrs, mywraps.example2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'__main__'"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "__name__"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'__annotations__': {},\n",
      " '__dict__': {'__wrapped__': <function func_in_main1 at 0x00000000044F1620>},\n",
      " '__doc__': 'Docstr func main1',\n",
      " '__module__': '__main__',\n",
      " '__name__': 'func_in_main1'}\n"
     ]
    }
   ],
   "source": [
    "@mywraps.decorator_wraps\n",
    "def func_in_main1():\n",
    "    \"\"\"Docstr func main1\"\"\"\n",
    "    print('func main1')\n",
    "\n",
    "print_attrs(attrs, func_in_main1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
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   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<function mywraps.example3>"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "mywraps.example3"
   ]
  },
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   "cell_type": "code",
   "execution_count": 12,
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "decorated func wraps and update\n",
      "ex3\n"
     ]
    }
   ],
   "source": [
    "mywraps.example3()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'__annotations__': {},\n",
      " '__dict__': {'__wrapped__': <function example3 at 0x00000000044CAA60>},\n",
      " '__doc__': 'Docstr ex3',\n",
      " '__module__': 'mywraps',\n",
      " '__name__': 'example3'}\n"
     ]
    }
   ],
   "source": [
    "print_attrs(attrs, mywraps.example3)"
   ]
  }
 ],
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mywrap.py

from functools import (
    wraps,
    update_wrapper
)

# http://docs.python.jp/3.5/library/functools.html#functools.update_wrapper

def decorator_nowraps(f):
    def wrapper(*args, **kwds):
        print('decorated func nowarps')
        return f(*args, **kwds)
    return wrapper


def decorator_wraps(f):
    @wraps(f)
    def wrapper(*args, **kwds):
        print('decorated fun wraps')
        return f(*args, **kwds)
    return wrapper


def decorator_update_wrapper(f):
    def wrapper(*args, **kwds):
        print('decorated func wraps and update')
        return f(*args, **kwds)
    return update_wrapper(wrapper, wrapped=f)


@decorator_nowraps
def example1():
    """Docstr ex1"""
    print('example1')


@decorator_wraps
def example2():
    """Docstr ex2"""
    print('ex2')


@decorator_update_wrapper
def example3():
    """Docstr ex3"""
    print('ex3')