<div dir="ltr"><div class="gmail_extra">Hello,</div><div class="gmail_extra"><br></div><div class="gmail_extra">> <span style="font-size:12.8px">using the Maybe monad would be useful.</span><span style="font-size:12.8px"> </span></div><div class="gmail_extra"><span style="font-size:12.8px"><br></span></div><div class="gmail_extra"><span style="font-size:12.8px">But he already is? Anyway, `(x >>= f) == join (fmap f x)`</span></div><div class="gmail_extra"><span style="font-size:12.8px"><br></span></div><div class="gmail_extra"><span style="font-size:12.8px">Best regards,</span></div><div class="gmail_extra"><span style="font-size:12.8px">Marcin Mrotek</span></div></div>