[darkf]

>You can't do that in Haskell either, and any FP purist would blanch at a statement like that.

Obviously you've never met State and/or lens then.

Yes, you can do it -- and no, I never said it should follow pure FP principles.

[lmm]

But if you write a State equivalent of "x += 1" in Python then you can use it in a lambda too.