Archive for the ‘python’ Category

shut up, you dummy 7-bit Python

Friday, March 23rd, 2007

I’m working on an unicode-aware application. I like to use print to debug programs, but in this case it was nightmare. The most popular result of print was:

UnicodeDecodeError: 'ascii' codec can't decode byte 0xXX in position 0: ordinal not in range(128)

I spent two hours fixing it, and I hope it’s done. The solution is one of the ugliest hack I ever written, but it solves the pain.

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execute an XPath and get the line numbers

Monday, March 5th, 2007

I’m investigating the structure of an XML file. The best tool is an usual text editor (vim), but I need to look at some specific tags in some specific contexts. The idea is to execute an XPath and somehow to get to the location in the editor. Remembering that I saw something interesting while playing with libxml internals, I re-checked… And bingo! I’ve written a script which executes an XPath and prints the result together with the line number of the source XML file.

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plasTeX

Wednesday, October 25th, 2006

Seems interesting: plasTeX is a LaTeX document processing framework written entirely in Python. It currently comes bundled with an XHTML renderer (including multiple themes), as well as a way to simply dump the document to a generic form of XML. Other renderers can be added as well and are planned for future releases.

scons signatures for Python actions

Thursday, August 24th, 2006

Finally, I traced out why time-to-time my functional tests stop passing.
* Some steps are associated with Python functions.
* Signatures of such steps depend on the code of the functions.
* If the code of a function is changed, the signature is changes, and the step is considered out-of-date.
Therefore, small changes in code lead to changes in the build process.

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forcing python mode in vim

Wednesday, August 23rd, 2006

To force the python mode for a file, add the following comment at the beginning:

# -*- mode: python -*-

It’s also possible to add other options as well. Unfortunately, I don’t remember the term for such comment, so I can’t find its descrition in the vim documentation.

currently executing python file

Wednesday, August 16th, 2006

Here is a way to get the currently executing Python file:

print (lambda x:x).func_code.co_filename

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parsing latex log files

Thursday, August 10th, 2006

In mary cases, LaTeX should be run several times to get the correct result (for example, to resolve cross-references). The only way to detect if re-run is required is to analyze the log file. I haven’t found anything ready to use, so I’ve written it myself.

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python trap

Wednesday, August 2nd, 2006

What will this code print?

for item in ('aaa'): print item

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Python for Lisp Programmers

Thursday, January 5th, 2006

A small Lisp vs Python article: “Python for Lisp Programmers“. The title is very untraditional, one expects Python and Lisp swapped.