linear recursion versus tree recursion

README.md

See https://cesquivias.github.io/blog/2014/10/13/writing-a-language-in-truffle-part-1-a-simple-slow-interpreter/.

Also https://mitpress.mit.edu/sicp/full-text/book/book-Z-H-11.html#%_sec_1.2.1.

Usage

(fibonacci 10)

linear.lsp

(define fibonacci
  (lambda (n)
    (if (< n 2)
        1
        (+ (fibonacci (- n 1))
           (fibonacci (- n 2))))))

tree.lsp

(define fibonacci
  (lambda (n)
    (define iter
      (lambda (i n1 n2)
        (if (= i 0)
            n2
            (iter (- i 1)
                  n2
                  (+ n1 n2)))))
    (iter n 0 1)))