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<body><div style="font-family: sans-serif;"><div class="plaintext" style="white-space: normal;"><p dir="auto">I had a correspondence about this a long time ago, but alas I cannot find it (no great keyword choices).</p>
<p dir="auto">Probably the best source I can point you at is this discussion in Franz's Allegro documentation:</p>
<p dir="auto"><a href="https://franz.com/support/documentation/10.1/doc/implementation.htm#nested-conditionals-3" style="color: #3983C4;">https://franz.com/support/documentation/10.1/doc/implementation.htm#nested-conditionals-3</a></p>
<br><p dir="auto">Unfortunately, even this discussion does not have pointers to the specification.</p>
<p dir="auto">On 13 Mar 2023, at 16:06, Tim McNerney wrote:</p>
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<div dir="auto">
Would someone mind quoting “chapter and verse”?
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<div>Somehow, even those of us with decades of Common Lisp experience, all trying to follow the drama of the X3J13 committee, a bunch of us “missed the memo” about this convenient, allegedly legal, but “buyer beware” syntax.
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<div>Yes, I absolutely hate
<div> #+foo :keyword #+foo argument too. </div>
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<div dir="ltr">--Tim</div>
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<blockquote type="cite">On Mar 13, 2023, at 14:00, Robert Goldman <rpgoldman@sift.info> wrote:<br>
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<p dir="auto">On 13 Mar 2023, at 12:42, Ron Garret wrote:</p>
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<p dir="auto">Oh, forgot to add...</p>
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<p dir="auto">On Mar 13, 2023, at 10:20 AM, Arthur Cater <arthur.cater@ucd.ie> wrote:</p>
<p dir="auto">It never previously occurred to me that read time conditionals could be nested.</p>
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<p dir="auto">Just because you can do something doesn't mean you should.</p>
<p dir="auto">rg</p>
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<p dir="auto">I was surprised myself to see</p>
<pre style="margin-left: 15px; margin-right: 15px; padding: 5px; background-color: #F7F7F7; border-radius: 5px 5px 5px 5px; overflow-x: auto; max-width: 90vw;"><code style="margin: 0 0; border-radius: 3px; background-color: #F7F7F7; padding: 0px;">#+foo #+foo
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<p dir="auto">used to make two s-expressions (in)visible in the presence (absence) of the <code style="margin: 0 0; padding: 0 0.25em; border-radius: 3px; background-color: #F7F7F7;">:foo</code> feature. But it's clearly dictated by the spec, and is often handy when, for example one might want to have something conditionally in a property list</p>
<pre style="margin-left: 15px; margin-right: 15px; padding: 5px; background-color: #F7F7F7; border-radius: 5px 5px 5px 5px; overflow-x: auto; max-width: 90vw;"><code style="margin: 0 0; border-radius: 3px; background-color: #F7F7F7; padding: 0px;">(list :prop1 12
#+foo #+foo
:foo 'bar)
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<p dir="auto">In my opinion, that's clearer than</p>
<pre style="margin-left: 15px; margin-right: 15px; padding: 5px; background-color: #F7F7F7; border-radius: 5px 5px 5px 5px; overflow-x: auto; max-width: 90vw;"><code style="margin: 0 0; border-radius: 3px; background-color: #F7F7F7; padding: 0px;">(list :prop1 12
#+foo :foo #+foo 'bar)
</code></pre>
<p dir="auto">which obscures reading this as a property list and obscures the fact that the two elements of the list are going to be swapped in or out based on a single feature.</p>
<pre style="margin-left: 15px; margin-right: 15px; padding: 5px; background-color: #F7F7F7; border-radius: 5px 5px 5px 5px; overflow-x: auto; max-width: 90vw;"><code style="margin: 0 0; border-radius: 3px; background-color: #F7F7F7; padding: 0px;">(append (list :prop 12) #+foo (list :foo 'bar) )
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<p dir="auto">is not an alternative particularly pleasing to me, but YMMV. It's certainly very busy.</p>
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