<div dir="ltr"><div><div>This isn't a typo. The docs are talking about the properties of the symbol tables for interned and unreadable symbols. There is no symbol table for uninterned symbols, so it wouldn't mean anything to talk about it.<br>
<br></div>Here's what this means for an interned symbol: you can create one, and while a reference to it exists, it stays in the symbol table. Any time you intern the same string, you'll get back that symbol. However, if all references to that symbol vanish, the symbol table is free to release that symbol. If anyone interns the same string again later, a new symbol will be created. For nearly all purposes, this is completely transparent, because you couldn't possibly have a copy of the old symbol to compare. There's almost no way to tell that the symbol you got before and the one you got after were different. The only way you'd ever know would be either by tracking memory use statistics, or by comparing the results of something like eq-hash-code, neither of which should be surprising to find out behaves impurely.<br>
</div></div><div class="gmail_extra"><br clear="all"><div>Carl Eastlund</div>
<br><br><div class="gmail_quote">On Mon, Jan 27, 2014 at 5:53 PM, Jos Koot <span dir="ltr"><<a href="mailto:jos.koot@gmail.com" target="_blank">jos.koot@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<u></u>
<div>
<div dir="ltr" align="left"><font color="#0000ff" face="Courier New"><span>It appears that my previous email was not sent
completely. Sorry for that. Here is the complete question.</span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Courier New"><span></span></font> </div>
<div dir="ltr" align="left"><span><div class="im">
<div><font color="#0000ff" face="Courier New"><span>Hi to all,</span></font></div>
<div><font color="#0000ff" face="Courier New"><span></span></font> </div>
<div><font color="#0000ff" face="Courier New"><span>Section "3.6 symbols" of the Racket reference manual
states:</span></font></div>
<div><font color="#0000ff" face="Courier New"><span></span></font> </div>
</div><div><span><font face="Courier New"><font color="#0000ff"><font>Interned and unreadable symbols are only weakly held
... but a symbol maay disappear when ... used as the key in a weak hash table
..."<span>.</span></font></font></font></span></div>
<div><span><font face="Courier New"><font color="#0000ff"><font><span></span></font></font></font></span> </div>
<div><span><font face="Courier New"><font color="#0000ff"><font><span>I would
understand:</span></font></font></font></span></div>
<div><span><font face="Courier New"><font color="#0000ff"><font><span></span></font></font></font></span> </div>
<div><span><font face="Courier New"><font color="#0000ff"><font><span><span><font face="Courier New"><font color="#0000ff"><font>UNINTERNED and unreadable symbols are only weakly held ... but a
symbol may disappear when ... used as the key in a weak hash table ..."<span>.</span></font></font></font></span></span></font></font></font></span></div>
<div><span><font face="Courier New"><font color="#0000ff"><font><span><span><font face="Courier New"><font color="#0000ff"><font><span></span></font></font></font></span></span></font></font></font></span> </div>
<div><span><font face="Courier New"><font color="#0000ff"><font><span><span><font face="Courier New"><font color="#0000ff"><font><span>May be just a typo, but as I am not sure I
understand the docs well, I post my question here instead of posting a bug
report.</span></font></font></font></span></span></font></font></font></span></div>
<div><span><font face="Courier New"><font color="#0000ff"><font><span><span><font face="Courier New"><font color="#0000ff"><font><span></span></font></font></font></span></span></font></font></font></span> </div>
<div><span><font face="Courier New"><font color="#0000ff"><font><span><span><font face="Courier New"><font color="#0000ff"><font><span>Greetings,
Jos</span></font></font></font></span></span></font></font></font></span></div></span></div></div>
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<br></blockquote></div><br></div>