Handle process and terminal correctly.

src/ansi.scm

@@ -39,6 +39,7 @@
   ansi-string-length
   ansi-paragraph-format
   ansi-string
+  clrscr
   ansi-tests!
   )
 
@@ -211,6 +212,11 @@
 				(cons arg res)
 				(cons arg (cons (apply ansi (reverse kws)) res))))))))))
 
+ ;; Clears the entire screen and positions cursor in the upper-left
+ ;; corner.
+ (define (clrscr)
+   (display "\x1b[0m\x1b[2J\x1b[0;0H"))
+
  ;; Performs ANSI module self-tests.
  (define (ansi-tests!)
    (run-tests