2lines.lino

define point {
  number x, y;
  draw { &draw_point; } 
}

define line {
  point start, end;
  draw { &draw_line; } 
}

define hline  extends line {
  number y, length;
  constraints {
    start.y = end.y;
    start.y = y;
    start.x + length = end.x;
  }
}

point P, Q;
line A;
hline B;


constraints {
  A.start = (1,2);
  B.length = 10;
  A = B + 100;
  P = B.end;
}

__END__

sub draw_line { 
  my $env = shift;
  my $s = hash2str($env->var_hash);
  print "DRAWING LINE ($s)\n";
}

sub draw_point {
  my $env = shift;
  my $s = hash2str($env->var_hash);
  print "DRAWING POINT ($s)\n";
}