Haskell has one of the _clearest_ distinctions between red/blue functions that I know. Functions that perform I/O (sans unsafePerformIO and other strange things

Haskell has one of the _clearest_ distinctions between red/blue functions that I know. Functions that perform I/O (sans unsafePerformIO and other strange things) are very explicit about it (by returning an `IO` monad). Most other languages (static or not) are equally explicit (returning a `Promise<A>` and not an `IO a` but it's very similar. Most differences are because call-by-need vs. call-by-value language semantics (Haskell being non-strict and the I/O not coming out of "thin air" but coming from somewhere - but that's kind of a different point than function color type)