Laziness

• More points for lazy evaluation
• https://www.reddit.com/r/haskell/comments/5xge0v/today_i_used_laziness_for/
• http://stackoverflow.com/questions/23893320/why-isnt-this-recursive-function-being-optimized-haskell/23893575#23893575

Philip Walder: With distribution becoming so important, we need to focus on programs that run on multiple machines, sending values from one to the other. When you send a value, you probably want it to be the value itself (eager evaluation), rather than a program (and the values of all the free variables of the program) that can be evaluated to yield the value. So, in the distributed world, I think it would be better to be eager by default but make it easy to be lazy when you want.

lazy in the spine, strict in the leaves.