From cae3cc6d7bdfa27aa18ad4ebcb0f6724ee5d5698 Mon Sep 17 00:00:00 2001
From: rsiddharth <s@ricketyspace.net>
Date: Sat, 17 Aug 2019 09:31:19 -0400
Subject: Add (net ricketyspace sicp two thirtytwo).

---
 net/ricketyspace/sicp/two/thirtytwo.scm | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 net/ricketyspace/sicp/two/thirtytwo.scm

(limited to 'net/ricketyspace')

diff --git a/net/ricketyspace/sicp/two/thirtytwo.scm b/net/ricketyspace/sicp/two/thirtytwo.scm
new file mode 100644
index 0000000..31d6446
--- /dev/null
+++ b/net/ricketyspace/sicp/two/thirtytwo.scm
@@ -0,0 +1,16 @@
+;;;; License: CC0-1.0
+
+(define-module (net ricketyspace sicp two thirtytwo)
+  #:export (subsets))
+
+(define (subsets s)
+  (if (null? s)
+      (list '())
+      (let ((rest (subsets (cdr s))))
+        (append rest (map (lambda (item) (cons (car s) item)) rest)))))
+
+;;; Guile REPL
+;;;
+;;; scheme@(guile-user)> ,use (net ricketyspace sicp two thirtytwo)
+;;; scheme@(guile-user)> (subsets '(1 2 3))
+;;; $6 = (() (3) (2) (2 3) (1) (1 3) (1 2) (1 2 3))
-- 
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