Added clear screen function

1 files changed, 15 insertions, 2 deletions

diff --git a/kernel/writer.dats b/kernel/writer.dats
index cd6f5d7..3e75a90 100644
--- a/kernel/writer.dats
+++ b/kernel/writer.dats
@@ -51,7 +51,6 @@ staload WRITER = {
   end
 }
 
-
 fun put_char (c : char, writer: &writer) : void = let
   val buf = get_buffer()
   val pos = writer.position
@@ -62,12 +61,16 @@ in
     in
       if (new_pos < N) then
         writer.position := new_pos
+      else
+        clear_screen()
     end
   else (
     buf.1->[writer.position] := @{ ascii_character = c, color_code = writer.color_code};
 
     if (pos < N - 1) then
-      writer.position := succ(pos));
+      writer.position := succ(pos)
+    else
+      clear_screen());
 
   let prval() = eat_buffer buf in () end
 end
@@ -80,3 +83,13 @@ implement put_string (str : string) : void = let
   prval() = fpf(pf)
 in  end
 
+implement clear_screen() : void = let
+  val (pf, fpf | p_val) = $WRITER.getref()
+  fun loop {n : nat | n < N - 1} .<N-n>. (i : int n, wr : &writer) : void = 
+    (put_char('\0', wr); if (i < N - 2) then loop(i+1,wr))
+in
+  !p_val.position := 0;
+  loop(0,!p_val);
+  !p_val.position := 0;
+  let prval() = fpf(pf) in () end
+end