March 2014 update

Task/Metaprogramming/Common-Lisp/metaprogramming-3.lisp

@@ -1,8 +1,29 @@
-;; The -> notation is not part of Lisp, it is used in examples indicate the output of a form.
-;;
-;;
-(comprehend 'list-monad (cons x y) (x '(1 2 3)) (y '(A B C)))
-
-     -> ((1 . A) (1 . B) (1 . C)
-         (2 . A) (2 . B) (2 . C)
-         (3 . A) (3 . B) (3 . C))
+(system::expand-form
+    '(loop for count from 1
+           for x in '(1 2 3 4 5)
+           summing x into sum
+           summing (* x x) into sum-of-squares
+           finally
+             (return
+               (let* ((mean (/ sum count))
+                      (spl-var (- (* count sum-of-squares) (* sum sum)))
+                      (spl-dev (sqrt (/ spl-var (1- count)))))
+                 (values mean spl-var spl-dev))))))
+(BLOCK NIL
+ (LET ((COUNT 1))
+  (LET ((#:LIST-3230 '(1 2 3 4 5)))
+   (LET ((X NIL))
+    (LET ((SUM-OF-SQUARES 0) (SUM 0))
+     (TAGBODY SYSTEM::BEGIN-LOOP
+      (WHEN (ENDP #:LIST-3230) (GO SYSTEM::END-LOOP))
+      (SETQ X (CAR #:LIST-3230))
+      (PROGN (SETQ SUM (+ SUM X))
+       (SETQ SUM-OF-SQUARES (+ SUM-OF-SQUARES (* X X))))
+      (PSETQ COUNT (+ COUNT 1)) (PSETQ #:LIST-3230 (CDR #:LIST-3230))
+      (GO SYSTEM::BEGIN-LOOP) SYSTEM::END-LOOP
+      (RETURN-FROM NIL
+       (LET*
+        ((MEAN (/ SUM COUNT))
+         (SPL-VAR (- (* COUNT SUM-OF-SQUARES) (* SUM SUM)))
+         (SPL-DEV (SQRT (/ SPL-VAR (1- COUNT)))))
+        (VALUES MEAN SPL-VAR SPL-DEV)))))))))