sicp

sicp sandbox.
git clone git://git.ricketyspace.net/sicp.git
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commit d4deb2fc72cd436a874987c67567c104e71c3608
parent 246359ab7964855b02d7994588d8df10541ab599
Author: rsiddharth <s@ricketyspace.net>
Date:   Sat, 17 Jun 2017 13:02:23 +0000

net: Add module (net ricketyspace sicp one twentyone).

* net/ricketyspace/sicp/one/twentyone.scm: New file.

Diffstat:
net/ricketyspace/sicp/one/twentyone.scm | 42++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+), 0 deletions(-)

diff --git a/net/ricketyspace/sicp/one/twentyone.scm b/net/ricketyspace/sicp/one/twentyone.scm @@ -0,0 +1,42 @@ +;;;; Under Creative Commons Attribution-ShareAlike 4.0 +;;;; International. See +;;;; <https://creativecommons.org/licenses/by-sa/4.0/>. + +(define-module (net ricketyspace sicp one twentyone) + #:export (sm-divisor-of-199 + sm-divisor-of-1999 + sm-divisor-of-19999)) + +(define (small-divisor n) + (find-divisor n 2)) + +(define (find-divisor n test-divisor) + (cond ((> (square test-divisor) n) n) + ((divides? test-divisor n) test-divisor) + (else (find-divisor n (+ test-divisor 1))))) + +(define (divides? a b) + (= (remainder b a) 0)) + +(define (square x) + (expt x 2)) + +(define (sm-divisor-of-199) + (small-divisor 199)) + +(define (sm-divisor-of-1999) + (small-divisor 1999)) + +(define (sm-divisor-of-19999) + (small-divisor 19999)) + +;;; +;;; scheme@(guile-user)> ,use (net ricketyspace sicp one twentyone) +;;; ... +;;; scheme@(guile-user)> (sm-divisor-of-199) +;;; $3 = 199 +;;; scheme@(guile-user)> (sm-divisor-of-1999) +;;; $4 = 1999 +;;; scheme@(guile-user)> (sm-divisor-of-19999) +;;; $5 = 7 +;;;