From da27cf183a33969177ffe34b969cf1f199f2ab9d Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <janneke@gnu.org>
Date: Sun, 14 Aug 2016 01:40:45 +0200
Subject: [PATCH] lib/srfi/srfi-1.scm: add append-map, filter, find.

---
 lib/srfi/srfi-1.scm | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 lib/srfi/srfi-1.scm

diff --git a/lib/srfi/srfi-1.scm b/lib/srfi/srfi-1.scm
new file mode 100644
index 00000000..8bc8d838
--- /dev/null
+++ b/lib/srfi/srfi-1.scm
@@ -0,0 +1,15 @@
+(define (find pred lst)
+  (let loop ((lst lst))
+    (if (null? lst) #f
+        (if (pred (car lst)) (car lst)
+            (loop (cdr lst))))))
+
+(define (filter pred lst)
+  (let loop ((lst lst))
+    (if (null? lst) '()
+        (if (pred (car lst))
+            (cons (car lst) (loop (cdr lst)))
+            (loop (cdr lst))))))
+
+(define (append-map f lst)
+  (apply append (map f lst)))