Data commit

Task/Vigen-re-cipher/TXR/vigen-re-cipher.txr

@@ -0,0 +1,23 @@
+@(next :args)
+@(do
+   (defun vig-op (plus-or-minus)
+     (op + #\A [mod [plus-or-minus (- @1 #\A) (- @2 #\A)] 26]))
+
+   (defun vig (msg key encrypt)
+     (mapcar (vig-op [if encrypt + -]) msg (repeat key))))
+@(coll)@{key /[A-Za-z]/}@(end)
+@(coll)@{msg /[A-Za-z]/}@(end)
+@(cat key "")
+@(filter :upcase key)
+@(cat msg "")
+@(filter :upcase msg)
+@(bind encoded @(vig msg key t))
+@(bind decoded @(vig msg key nil))
+@(bind check @(vig encoded key nil))
+@(output)
+text:  @msg
+key:   @key
+enc:   @encoded
+dec:   @decoded
+check: @check
+@(end)