Pro Simple, flexible, hackable FFI
max = ffi "Math.round(%1,%2)"
concat, though they must expose an explicit number of parameters to Fay.
Pro Subset of Haskell - nothing new to learn
Since Fay is a subset of Haskell - Lazy, statically typed, and pure by default. There's no new syntax to learn, and no surprises when it comes to the semantics of your code. This extends into function names as well - Fay programmers can use familiar functions such as