>>83 Why do you think utf8_isspace() is worse than .decode('utf8').isspace()? I think utf8_isspace() is better simply because in the latter case, the programmer is likely to simply use isspace() instead and be wrong.

>>84 Are you saying you would prefer cat refuse to type out a file because $LANG was set wrong?

And to be clear: The user isn't always aware what's wrong. Many users insist that utf-8 is wrong on IRC because many people outside the US don't use utf-8 on irc (for whatever legacy reason). IRC doesn't transcode for people, and the protocol doesn't specify the character set. It's a mess, but it's a mess that the programmers ultimately have to deal with.