Initial data commit

Task/Caesar-cipher/Red/caesar-cipher.red

@@ -0,0 +1,27 @@
+Red ["Ceasar Cipher"]
+
+rot: func [
+    char [char!]
+    key  [number!]
+    ofs  [char!]
+][
+    to-char key + char - ofs // 26 + ofs
+]
+
+caesar: function [
+    src [string!]
+    key [integer!]
+][
+    lower: charset [#"a" - #"z"]
+    upper: charset [#"A" - #"Z"]
+    parse src [
+        any [
+            change s: [lower (o: #"a") | upper (o: #"A")] (rot s/1 key o)
+          | skip
+        ]
+    ]
+    src
+]
+
+encrypt: :caesar
+decrypt: func spec-of :caesar [caesar src negate key]