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Python 2.5.1: Potential Bug in "print"
- From: Mike MacFerrin <Michael dot MacFerrin at Colorado dot EDU>
- To: cygwin at cygwin dot com
- Date: Thu, 20 Sep 2007 00:22:41 -0600 (MDT)
- Subject: Python 2.5.1: Potential Bug in "print"
I'm a grad student in a Compiler Tools course, and (as part of the course) we're compiling a subset of the Python language down to C, and from there to x86 Assmebly. Our code has to pass a lengthy series of test-suites for correctness (comparing the output of our compiled C Code with that of native Python code), and I stumbled across what seems to be a quirky bug in Cygwin Python 2.5.1 (the most recent install).
To the point. If I run a simple two-line Python module:
print 0.0
print -0.0
...it gives the following output (as you'd expect):
0.0
0.0
However, if I remove the first line:
print -0.0
...I get...
-0.0
It seems to matter whether I've previously called "print 0.0" in the module. No other "print <float>" commands make a difference. Obviously, that seems strange (and doesn't follow the Python language definition).
That behavior doesn't show up in other installs of Python I've seen (IDLE, Windows command-line, or Linux command-line), just in Cygwin.
I'm not sure if this bug has been identified yet (it's a quirky corner case, and I didn't see anything to this affect in the Archives), but I thought I'd throw that out there. Run python and check for yourself if you wanna see it (from the shell it always prints "-0.0", but from a file it's inconsistent. Either way, it should just spit out "0.0").
In the meantime, I'm a bit frustrated that my code fails certain tests at home on Cygwin (due to no error of my own), but otherwise passes on the professor's box (MacOS command line). Eh, I s'pose it's better than vice-versa, but still.
Any suggestions or workarounds?
Thanks,
- Mike
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