The mapping function

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Lecture 2 - Page 21 : 35

Programming Paradigms
Recursion and Higher-order Functions

The mapping function

It is now time to study the implementation of the mapping function. We program a function called mymap in order not to redefine Scheme's own mapping function (a standard function in all Scheme implementations).

We show a simple implementation of map - called mymap

(define (mymap f lst)
  (if (null? lst)
      '()
      (cons (f (car lst))
            (mymap f (cdr lst)))))

An implementation of map. This is not a good implementation because the recursive call is not a tail call. We leave it as an exercise to make a memory efficient implementation with tail recursion - see the exercise below.

Iterative mapping function

Table exercise: transposing, row elimination, and column elimination.