Why does BODS casting to int of value '.000' returns 1 and not 0?

$i = cast('.0000', 'integer');

print('Int implicit conversion : ' || $i);
Returns 1

while

$i = cast('0.0000', 'integer');

print('Int implicit conversion : ' || $i);

Returns 0

Is there a reason or explanation as to why BODS assumes that no leading integer = 1?