diff options
| -rw-r--r-- | dbc2.lsp | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/dbc2.lsp b/dbc2.lsp index 21089ba..657d297 100644 --- a/dbc2.lsp +++ b/dbc2.lsp @@ -1,5 +1,8 @@ (defmacro unless (test :rest body) - `(if (not ,test) (progn ,@body))) + `(if (not ,test) (progn ,@body))) +(defmacro assert (test) + `(unless ,test + (error "assert: value is false." ',test))) (defun sum (sequence) (let ((res 0)) (for ((xs sequence (cdr xs))) @@ -7,11 +10,11 @@ (setq res (+ res (car xs)))))) (defun average-of-absolutes (values) (the <list> values) - (unless (> (length values) 0) - (error "average-of-absolutes requires non-null list" values)) + ;; requires non-null list + (assert (> (length values) 0)) (let ((res (quotient (sum values) (length values)))) - (unless (>= res 0) - (error "average-of-absolutes must ensure positive result" res)) - (the <fixnum> res))) + ;; must ensure positive result + (assert (>= res 0)) + (the <fixnum> res))) ;; (average-of-absolutes '(1 3)) ;; (average-of-absolutes '()) |