[Python-Dev] Divorcing str and unicode (no more implicit conversions). (original) (raw)

Martin Blais blais at furius.ca
Mon Oct 3 08:09:13 CEST 2005

Hi.

Like a lot of people (or so I hear in the blogosphere...), I've been experiencing some friction in my code with unicode conversion problems. Even when being super extra careful with the types of str's or unicode objects that my variables can contain, there is always some case or oversight where something unexpected happens which results in a conversion which triggers a decode error. str.join() of a list of strs, where one unicode object appears unexpectedly, and voila! exception galore. Sometimes the problem shows up late because your test code doesn't always contain accented characters. I'm sure many of you experienced that or some variant at some point.

I came to realize recently that this problem shares strong similarity with the problem of implicit type conversions in C++, or at least it feels the same: Stuff just happens implicitly, and it's hard to track down where and when it happens by just looking at the code. Part of the problem is that the unicode object acts a lot like a str, which is convenient, but...

What if we could completely disable the implicit conversions between unicode and str? In other words, if you would ALWAYS be forced to call either .encode() or .decode() to convert between one and the other... wouldn't that help a lot deal with that issue?

How hard would that be to implement? Would it break a lot of code? Would some people want that? (I know I would, at least for some of my code.) It seems to me that this would make the code more explicit and force the programmer to become more aware of those conversions. Any opinions welcome.

cheers,

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