<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 15 Feb 2011, at 15:21, Marco Antoniotti wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On Feb 15, 2011, at 14:36 , Attila Lendvai wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><blockquote type="cite">- The idea that COMPARE returns symbols also seems weird to me. Wouldn't it be better to return numbers (-1, 0, +1 or NIL)? Can't immediately tell why, though.<br></blockquote><br><br>you need to return well-known identities that communicate the result.<br>-1,0,+1 are the easy way for well-known identities in C. in CL,<br>symbols provide a much nicer framework to deal with well-known<br>identities IMO.<br></div></blockquote><div><br></div><div>That was the thinking.</div></div></div></blockquote><div><br></div><div>OK.</div><br><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><blockquote type="cite"><div><blockquote type="cite">- Shouldn't there also be a hash-code generic function that can be specialized alongside AEQUALIS? This also exists in Java and C#, and could make this immediately more useful (and would be much harder to add later as an afterthought). Many CL implementation add an :sxhash option to make-hash-table, where such a hash-code function could be used.<br></blockquote><br><br>a big +1 for the above.<br></div></blockquote><div><br></div><div>You should but:</div><div><br></div><div><ul class="MailOutline"><li>As in Java (and FWIU in C#) there are no "easy" ways (for an appropriate definition of "easy") to enforce the protocol.</li><li>What would be the default? Something like</li></ul><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span><font class="Apple-style-span" face="'Courier New'"><b>(defmethod hash-code ((x t)) (sxhash x))</b></font></div></div><div><br></div><div><br></div><div>If you think so, I can add it to the doc. Always with the caveat that there is no way to enforce the relationship between equality and hashing.</div></div></div></blockquote><div><br></div><div>Yes, that's an important remark. I nevertheless think it's important, because then people have at least a place to hang their hat on.</div><div><br></div><div>The default implementation for hash-code looks good to me.</div><br><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>Marco</div><div><br></div><div>PS. Yeah. AEQUALIS is very Latin :) Any synonym? I will just vote against EGAL, which I really don't like :)</div></div></div></blockquote><div><br></div><div>The good names are all taken, and I'm against adding a "?" to names in Common Lisp. ;)</div><div><br></div><div>What about "EQUIVALENT" or "EQUIV", or "EQUIVP"?</div><div><br></div><div><br></div><div>Pascal</div></div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; 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"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>-- </div><div>Pascal Costanza, <a href="mailto:pc@p-cos.net">mailto:pc@p-cos.net</a>, <a href="http://p-cos.net">http://p-cos.net</a></div><div>Vrije Universiteit Brussel</div><div>Software Languages Lab</div><div>Pleinlaan 2, B-1050 Brussel, Belgium</div><div><br></div></div></span></div></span></div></span></div></span></div></span></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline">
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