Implement the Salsa20 stream cipher.

1 files changed, 12 insertions, 0 deletions

diff --git a/typed-stream.rkt b/typed-stream.rkt
new file mode 100644
index 0000000..b674750
--- /dev/null
+++ b/typed-stream.rkt
@@ -0,0 +1,12 @@
+#lang racket
+(require racket/stream)
+
+(provide lazy-functional-stream-append)
+
+(define (lazy-functional-stream-append seq thunk)
+  (let-values ([(next? next) (sequence-generate seq)])
+    (let loop ()
+      (if (next?)
+          (let ([x (next)])
+            (stream-cons x (loop)))
+          (thunk)))))