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Course 4 - Summary

3. Only 7 keywords: fun, let_rec, match_with, type_of

2nd stack function:

let rec evenStack s = 
  match s with
  | NewStack    -> NewStack
  | Push (v,s') -> match (v%2)=0 with
                   | true -> Push (v,evenStack s')
                   | _    -> evenStack s';;

evenStack s;;

Generalization (filter):

let rec filterStack p s = 
  match s with
  | NewStack    -> NewStack
  | Push (v,s') -> match (p v) with
                   | true -> Push (v,filterStack p s')
                   | _    -> filterStack p s';;

filterStack (fun x -> (x%2)=0) s;;

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