[dfeltey]

I do understand your point, but purity is one of the defining characteristics of Haskell, and one of the features that differentiates it from most other languages, so I think it should be mentioned up front when introducing Haskell.

[davidw]

Mention it, maybe, but pointing out how great it is not to have to deal with that messy "real world" is bad marketing. It makes you think "oh, so all these benefits only exist in the magical fairy land and not in the real world where I work?"

[mercurial]

I understand what you're saying. It would be better to just talk about the enforced separation between pure code and code with side-effects, and explain that it's possible to structure a normal program so that it's mostly pure.

[tome]

It doesn't say you don't have to deal with 'that messy "real world"'! It is called Real World Haskell after all.

[seanmcdirmid]

I think it is great "truth in marketing", because going beyond purity requires talking about things like monads, and then they've lost most of their audience anyways.

It is better to lose those not interested in purity early rather than have those uninterested folks become disappointed later.