[Python-Dev] Criticism of execfile() removal in Python3

[Steven D'Aprano]

On Tue, Jun 10, 2014 at 05:23:12AM +0300, Paul Sokolovsky wrote:

> execfile() builtin function was removed in 3.0. This brings few
> problems:
> 
> 1. It hampers interactive mode - instead of short and easy to type
> execfile("file.py") one needs to use exec(open("file.py").read()).

If the amount of typing is the problem, that's easy to solve:

# do this once
def execfile(name):
    exec(open("file.py").read())

Another possibility is:

os.system("python file.py")


> 2. Ok, assuming that exec(open().read()) idiom is still a way to go,
> there's a problem - it requires to load entire file to memory. But
> there can be not enough memory. Consider 1Mb file with 900Kb comments
> (autogenerated, for example). execfile() could easily parse it, using
> small buffer. But exec() requires to slurp entire file into memory, and
> 1Mb is much more than heap sizes that we target.

There's nothing stopping alternative implementations having their own 
implementation-specific standard library modules.

steve at orac:/home/s$ jython
Jython 2.5.1+ (Release_2_5_1, Aug 4 2010, 07:18:19)
[OpenJDK Server VM (Sun Microsystems Inc.)] on java1.6.0_27
Type "help", "copyright", "credits" or "license" for more information.
>>> import java
>>> 


So you could do this:

from upy import execfile
execfile("file.py")

So long as you make it clear that this is a platform specific module, 
and don't advertise it as a language feature, I see no reason why you 
cannot do that.



-- 
Steven