Hi all,<div><br></div><div>I&#39;m puzzled by this cryptic notation in Typed Racket (copied from the docs):</div><div><br></div><div><table cellspacing="0" class="RktBlk" style="white-space:inherit;text-align:left;font-family:serif;background-color:rgb(255,255,255)">
<tbody><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"><span class="RktPn" style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span class="RktSym" style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://docs.racket-lang.org/ts-reference/special-forms.html#(form._((lib._typed-racket/base-env/prims..rkt)._~ce~bb~3a))" class="RktStxLink" style="text-decoration:none;color:black">:</a></span><span class="hspace" style="font-family:monospace"></span><span class="RktPn" style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">(</span><span class="RktPn" style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">[</span><span class="RktSym" style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)">x</span><span class="hspace" style="font-family:monospace"></span><span class="RktVar" style="font-family:monospace;white-space:inherit;color:rgb(38,38,128);font-style:italic">:</span><span class="hspace" style="font-family:monospace"></span><span class="RktSym" style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)"><a href="http://docs.racket-lang.org/ts-reference/type-ref.html#(form._((lib._typed-racket/base-env/base-types..rkt)._.Number))" class="RktStxLink" style="text-decoration:none;color:black">Number</a></span><span class="RktPn" style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">]</span><span class="RktPn" style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span><span class="hspace" style="font-family:monospace"></span><span class="RktSym" style="font-family:monospace;white-space:inherit;color:rgb(38,38,128)">x</span><span class="RktPn" style="font-family:monospace;white-space:inherit;color:rgb(132,60,36)">)</span></td>
</tr><tr style="white-space:inherit"><td style="padding-left:0px;padding-right:0px;vertical-align:baseline;white-space:inherit"><p style="margin:0px"><span class="RktOut" style="font-family:monospace;white-space:inherit;color:rgb(150,0,150)">- : (Number -&gt; Number : ((! False @ 0) | (False @ 0)) (0))</span></p>
<p style="margin:0px"><span class="RktOut" style="font-family:monospace;white-space:inherit;color:rgb(150,0,150)"><br></span></p></td></tr></tbody></table><br></div><div>What does the &quot;@ 0&quot; mean? I have searched all of the TR doc pages, but I see no explanation.</div>
<div><br></div><div>Thanks,</div><div>jmj</div><div><br></div>