(*
Title   : POP.MOD
LastEdit: 1/89
Author  : Kim Moser
System  : JPI's TopSpeed Modula-2 with PMI's Repertoire 1.5
Descrip : Pop routine tests.
*)

FROM SmartScreen IMPORT WriteAt;
FROM KbdInput IMPORT KeyHit, AnyKeyNum;

(*
    T    h    i    s         i    s         a         t    e    s    t    .
           T   h   i   s       i   s       a       t   e   s   t   .
                  T  h  i  s     i  s     a     t  e  s  t  .
                         T h i s   i s   a   t e s t .
                                This is a test.
                                012345678901234

           T   h   i   s       i   s       a       b   l   a   s   t   .
                  T  h  i  s     i  s     a     b  l  a  s  t  .
                         T h i s   i s   a   b l a s t .
                                This is a blast.
                                0123456789012345
*)

PROCEDURE PopAt( x, y, w: CARDINAL; s: ARRAY OF CHAR );
VAR t: ARRAY [0..128] OF CHAR;
    i, j, r, s: CARDINAL;
    Len: CARDINAL;
    Loop, Step: CARDINAL;
BEGIN
  Len := Length(s);
  LOOP
    Step := w DIV 2;
    Fill( ADR(t), SIZE(t), BYTE(' ') );
    SetLength( t, w );
    i := Len DIV 2;
    IF ODD(Len) THEN
      j := i;
    ELSE
      DEC(i);
      j := i+1;
    END;

    LOOP
      IF (i-Step) >= 0 THEN
        DEC(i, Step);
      ELSE
        EXIT;
      END;

      IF (j+Step) < Len THEN
        INC( j, Step );
      ELSE
        EXIT;
      END;

      t[
    END;

    END;

  END;
END PopAt;

BEGIN
  PopAt( 40, 10, 80, "This is a test." );
  PopAt( 40, 11, 80, "This isn't a test." );
END Pop;