exec_print.py

exec_print.py

from __future__ import print_function
import os
import sys
import six
from time import time
from random import choice
from string import Formatter
from string import ascii_letters
from inspect import currentframe

string_formatter = Formatter()

six.moves.builtins.std_print = print

def random_string(length=20):
    """
    generate a random string of given length
    """
    return "".join(choice(ascii_letters)
                   for _ in range(length))

class TextObject(object):
    __slots__ = ["code", "text"]

    def __init__(self, text, code):
        self.text = text
        self.code = code

    @classmethod
    def from_text(cls, text):
        keywords = {random_string(): kw for _, kw, _, _
                    in string_formatter.parse(text) if kw}

        code = ["__keywords={}"]
        line_code = "__keywords[\"{kw_name}\"] = {kw_statement}"
        for key, value in six.iteritems(keywords):
            code.append(line_code.format(kw_name=key,
                                         kw_statement=value))
            text = text.replace("{{{}}}".format(value),
                                "{{{}}}".format(key))

        return cls(text=text,
                   code="\n".join(code))


memoize = {}


def print(text, **kwargs):
    caller = currentframe().f_back

    text_obj = memoize.get(text)
    if not text_obj:
        memoize[text] = text_obj = TextObject.from_text(text)

    exec(text_obj.code, caller.f_globals, caller.f_locals)
    std_print(text_obj.text.format(**caller.f_locals["__keywords"]), **kwargs)


devnull = open(os.devnull, 'w')

name = "oded"
t = time()
for _ in range(50000):
  print("my name is {name} & 2*3={2*3}", file=devnull)
std_print("block took {0:.3f} seconds".format(time() - t))