Category Archives: short

Less than 250 words

Something Fishy with Python ASTs

Posted on Monday 19 March 2012 by J. D. Bartlett

$ python
Python 2.7.1+ (r271:86832, Apr 11 2011, 18:05:24) 
[GCC 4.5.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import ast
>>> m = ast.parse('from __future__ import division')
>>> m
<_ast.Module object at 0xb764418c>
>>> compile(m, '<string>', 'exec')
 at 0xb7636e78, file "<string>", line 1>

$ python

Python 2.7.1+ (r271:86832, Apr 11 2011, 18:05:24)

[GCC 4.5.2] on linux2

Type "help", "copyright", "credits" or "license" for more information.

>>> import ast

>>> m = ast.parse('from __future__ import division')

>>> m

<_ast.Module object at 0xb764418c>

>>> compile(m, '<string>', 'exec')

at 0xb7636e78, file "<string>", line 1>

Ok, so far so good. Now comes the interesting bit.

>>> import pickle
>>> m2 = pickle.loads(pickle.dumps(m))
>>> m2
<_ast.Module object at 0xb7651c0c>
>>> compile(m2, '<string>', 'exec')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1
SyntaxError: from __future__ imports must occur at the beginning of the file

>>> import pickle

>>> m2 = pickle.loads(pickle.dumps(m))

>>> m2

<_ast.Module object at 0xb7651c0c>

>>> compile(m2, '<string>', 'exec')

Traceback (most recent call last):

File "<stdin>", line 1, in <module>

File "<string>", line 1

SyntaxError: from __future__ imports must occur at the beginning of the file

When you parse an AST with a __future__ import, it looks as if it stores some hidden flags that suppress this error. These flags, if they exist, are … Continue reading →

Posted in short | Tagged mystery, parsing, python | 12 Comments

Again: Broadcom Wireless BCM43224, Ubuntu

Posted on Monday 6 February 2012 by J. D. Bartlett

Update 2013-02-27: This solution on Ask Ubuntu is much better, because it includes properly packaged things that should update when you upgrade Ubuntu. Update 2012-10-24: The patch is no longer available on Broadcom’s website, but it can be found here. … Continue reading →

Posted in short | Tagged broadcom, tips, troubleshooting, ubuntu, wireless | 4 Comments

Import Graphs for Python

Posted on Monday 24 January 2011 by J. D. Bartlett

I was doing some Trosnoth refactoring recently, and I wanted a tool that would draw import graphs of the Trosnoth subpackages. After a quick search of the Internet didn’t give me what I wanted, I set about to write my … Continue reading →

Posted in short | Tagged graphs, imports, programming, python, refactoring, tools, trosnoth | Comments Off

Welcome to the New-Look Sqizit

Posted on Wednesday 19 January 2011 by J. D. Bartlett

Today I’ve moved Sqizit to a new host, updated the theme, and fixed the formatting of old articles. For those interested, a brief history of Sqizit: In the distant past I tried starting blogs a few times (mostly on blogger.com), … Continue reading →

Posted in short | Tagged blogging | Comments Off

Category Archives: short

Something Fishy with Python ASTs

Again: Broadcom Wireless BCM43224, Ubuntu

Social Debate

Import Graphs for Python

Welcome to the New-Look Sqizit

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