Data commit

Task/Floyds-triangle/TXR/floyds-triangle.txr

@@ -0,0 +1,19 @@
+(defun flotri (n)
+  (let* ((last (trunc (* n (+ n 1)) 2))
+         (colw (mapcar [chain tostring length]
+                       (range (- last n -1) last)))
+         (x 0))
+    (each ((r (range* 0 n)))
+      (each ((c (range 0 r)))
+        (format t " ~*a" [colw c] (inc x)))
+      (put-line))))
+
+(defun usage (msg)
+  (put-line `error: @msg`)
+  (put-line `usage:\n@(ldiff *full-args* *args*) <smallish-positive-integer>`)
+  (exit 1))
+
+(tree-case *args*
+  ((num blah . etc) (usage "too many arguments"))
+  ((num) (flotri (int-str num)))
+  (() (usage "need an argument")))