[Python-Dev] PEP 0008 confusion - here it is, but don't use it? (original) (raw)

Skip Montanaro skip at pobox.com
Fri Aug 6 21:01:14 CEST 2004

From Raymond's checkin:

Programming Recommendations

- Code should be written in a way that does not disadvantage other
  implementations of Python (PyPy, Jython, IronPython, Pyrex, Psyco, and
  such).  For example, do not rely on CPython's efficient implementation
  of in-place string concatenation for statements in the form a+=b or
  a=a+b.  Those statements run more slowly in Jython.  In performance
  sensitive parts of the library, the ''.join() form should be used
  instead.  This will assure that concatenation occurs in linear time
  across various implementations.

I'm a bit confused. Why bother to speed up s+=t if we aren't supposed to use it?

Skip

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