But doesn't the whitespace issue gimp Python's lambda syntax? AFAIK you're limited to one expression or function call, to get around the fact that you can't just inline a completely new function (with its associated control flow structure).

And what about one-liners, a la Perl? Stack Overflow answers seem to imply either embedding newlines in your string, or using semi-colons (as a Python newbie... you can use semi-colons?!)