Until later? What later. An hour later?
Let's look at a few chapter titles of Real World Haskell.
Chapter 2: Types and Functions
Chapter 3: Defining types, streamlining functions
Chapter 4: Functional Programming
Chapter 6: Using Typeclasses
Chapter 14: Monads
Chapter 15: Programming with Monads
Chapter 18: Monad transformers
Re:Why Python is Slow: Looking Under the Hood
by Amadiro on Saturday May 10, 2014 @11:43AM
(#7725786)
It's a matter of perspective -- to someone who has taken a university class on lambda calculus/on logic that had a chapter on lambda calculus (e.g. as part of a M.Sc. in mathematical logic or CS), anything in RWH would probably seem extremely basic and superficial. It doesn't even introduce most of the basic things a first chapter in a book on lambda calculus would probably introduce you to.
My degree was also heavy on FP and LP alongside many other themes.
I think the biggest issue is with those developers that never got a degree or were unfortunate to land in a degree that taught programming languages instead of programming concepts.
Even the type system - you need to understand some tiny amount - you can only add ints to ints etc. The more complicated stuff, the type inference, the monads etc - can be ignored until later.
Haskell can be used without understanding - almost all programming languages can. That's why we have so many newbie bugs.