[Python-bugs-list] [ python-Feature Requests-491331 ] request sys.required_version

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Mon, 10 Dec 2001 14:25:43 -0800


Feature Requests item #491331, was opened at 2001-12-10 14:12
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Category: Python Library
Group: None
Status: Open
Priority: 5
Submitted By: Daniel Ortmann (dortmann)
Assigned to: Nobody/Anonymous (nobody)
Summary: request sys.required_version

Initial Comment:
In Perl, "require 5.04" conveniently specifies the
minimum level of Perl required to run the script.

I expected to find something similar in the Python sys
module, but this is as close as I can come:

import sys

assert (2,2) <= sys.version_info[:2], "python version
is too old!"


It seems to me that I should be able to say something like:

import sys
sys.required_version(2,2,0)

Thank you!


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>Comment By: Tim Peters (tim_one)
Date: 2001-12-10 14:25

Message:
Logged In: YES 
user_id=31435

Because Python has a full-blown exception system, it's 
generally better to test for the feature you need than to 
compare mysterious little integers.  For example, suppose 
you need list comprehensions.  You have no idea which 
version of Python first introduced them, and once you think 
you've got it figured out, readers of your code are going 
to have no idea that you *meant* "list comprehensions" when 
you compare sys.version_info against (2, 0).  So clearer 
all around is:

try:
.   eval("[i for i in range(2)]")
except SyntaxError:
.   raise ImportError, "I require list comprehensions"

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