From 7f64b4262ee7c71c6fe2593cd00b5606a14a8155 Mon Sep 17 00:00:00 2001
From: rsiddharth <s@ricketyspace.net>
Date: Thu, 26 Dec 2019 21:33:42 -0500
Subject: Add (net ricketyspace sicp two thirtynine).

* net/ricketyspace/sicp/two/thirtynine.scm: New file.
---
 net/ricketyspace/sicp/two/thirtynine.scm | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 net/ricketyspace/sicp/two/thirtynine.scm

(limited to 'net/ricketyspace')

diff --git a/net/ricketyspace/sicp/two/thirtynine.scm b/net/ricketyspace/sicp/two/thirtynine.scm
new file mode 100644
index 0000000..8c05587
--- /dev/null
+++ b/net/ricketyspace/sicp/two/thirtynine.scm
@@ -0,0 +1,22 @@
+;;;; License: CC0-1.0
+
+(define-module (net ricketyspace sicp two thirtynine)
+  #:use-module (net ricketyspace sicp two thirtyeight)
+  #:export (reverse-fr
+            reverse-fl))
+
+(define (reverse-fr sequence)
+  (fold-right (lambda (x y) (append y (list x))) '() sequence))
+
+(define (reverse-fl sequence)
+  (fold-left (lambda (x y) (append (list y) x)) '() sequence))
+
+;;;
+;;; Guile REPL
+;;;
+;;; scheme@(guile-user)> ,re (net ricketyspace sicp two thirtynine)
+;;; scheme@(guile-user)> (reverse-fr '(1 2 3 4 5 6))
+;;; $8 = (6 5 4 3 2 1)
+;;; scheme@(guile-user)> (reverse-fl '(1 2 3 4 5 6))
+;;; $9 = (6 5 4 3 2 1)
+;;;
-- 
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