<div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span style="color:rgb(0,0,0);font-family:Calibri,Arial,Helvetica,sans-serif;font-size:16px">I share your view that it is important to be able to use ComputedConstant "early" in the VM startup sequence. There is nothing inherent to the proposed API that *requires* a lambda or a method reference to be used. An anonymous or regular class, implementing Supplier would also do. Also, there is nothing fundamental that prevents us from *implementing* the API in a way it can be used "early".</span><br></blockquote><div dir="ltr"><br></div><div dir="ltr">If anonymous classes need to be used, what is its advantage over the initialization-on-demand holder idiom?</div><div dir="ltr">It seems to be completely inferior to initialization-on-demand holder idiom, except for being able to use it as instance fields.<br></div><div dir="ltr"><br></div><div>Glavo</div></div></div></div></div></div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jul 28, 2023 at 3:29 PM Per-Ake Minborg <<a href="mailto:per-ake.minborg@oracle.com" target="_blank">per-ake.minborg@oracle.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>
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Hi Rémi,<br>
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I share your view that it is important to be able to use ComputedConstant "early" in the VM startup sequence. There is nothing inherent to the proposed API that *requires* a lambda or a method reference to be used. An anonymous or regular class, implementing
Supplier would also do. Also, there is nothing fundamental that prevents us from *implementing* the API in a way it can be used "early".<br>
<br>
We do not add any keywords, the JEP is a pure library approach so, I do not foresee any backward compatibility issues.</div>
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Thanks for your feedback.</div>
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Best, Per</div>
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<div id="m_-1284864079631678419m_-4333802865184303049divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> <a href="mailto:forax@univ-mlv.fr" target="_blank">forax@univ-mlv.fr</a> <<a href="mailto:forax@univ-mlv.fr" target="_blank">forax@univ-mlv.fr</a>><br>
<b>Sent:</b> Thursday, July 27, 2023 6:36 PM<br>
<b>To:</b> Maurizio Cimadamore <<a href="mailto:maurizio.cimadamore@oracle.com" target="_blank">maurizio.cimadamore@oracle.com</a>><br>
<b>Cc:</b> Per-Ake Minborg <<a href="mailto:per-ake.minborg@oracle.com" target="_blank">per-ake.minborg@oracle.com</a>>; leyden-dev <<a href="mailto:leyden-dev@openjdk.org" target="_blank">leyden-dev@openjdk.org</a>>; John Rose <<a href="mailto:john.r.rose@oracle.com" target="_blank">john.r.rose@oracle.com</a>><br>
<b>Subject:</b> [External] : Re: Draft JEP Announcement: "Computed Constants"</font>
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<b>From: </b>"Maurizio Cimadamore" <<a href="mailto:maurizio.cimadamore@oracle.com" target="_blank">maurizio.cimadamore@oracle.com</a>><br>
<b>To: </b>"Remi Forax" <<a href="mailto:forax@univ-mlv.fr" target="_blank">forax@univ-mlv.fr</a>>, "Per-Ake Minborg" <<a href="mailto:per-ake.minborg@oracle.com" target="_blank">per-ake.minborg@oracle.com</a>><br>
<b>Cc: </b>"leyden-dev" <<a href="mailto:leyden-dev@openjdk.org" target="_blank">leyden-dev@openjdk.org</a>>, "John Rose" <<a href="mailto:john.r.rose@oracle.com" target="_blank">john.r.rose@oracle.com</a>><br>
<b>Sent: </b>Thursday, July 27, 2023 6:14:48 PM<br>
<b>Subject: </b>Re: Draft JEP Announcement: "Computed Constants"<br>
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<p>Hi Remi<br>
Yes, of course we were aware of that.<br>
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Think of this proposal as an API-driven approach (in the style of ThreadLocal, ClassValue, ScopedValue, ...) which delivers more or less the same feature, but w/o changing the language.</p>
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<p>One thing that's attractive about the API approach is that it is not limited to just static fields, but it can also work for instance fields as well.</p>
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<p>(that said, I agree the two jeps should somehow be related/link to each other)</p>
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<div>I see two problems with your suggested approach:<br>
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<div>- this proposal is on top of lambdas, which means that it can be used for applications but not for the VM startup because it can only be used after method handles sub-system have been initialized.</div>
<div>- this is not a backward compatible change, if you add a new keyword to static final fields, you can rewrite any public static final fields to a public lazy static final field,</div>
<div> by example, String.CASE_INSENSITIVE_ORDER which is rarely used but can not be changed with your proposal.</div>
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Maurizio</p>
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<div>Rémi<br>
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<div>On 27/07/2023 17:09, Remi Forax wrote:<br>
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<div>Hello,<br>
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<div>Are you aware of the lazy static final fields proposal ?<br>
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<div> <a href="https://bugs.openjdk.org/browse/JDK-8209964" target="_blank">
https://bugs.openjdk.org/browse/JDK-8209964</a><br>
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<div>In think both proposals should be merged.<br>
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<div>Rémi<br>
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<b>From: </b>"Per-Ake Minborg" <a href="mailto:per-ake.minborg@oracle.com" target="_blank">
<per-ake.minborg@oracle.com></a><br>
<b>To: </b>"leyden-dev" <a href="mailto:leyden-dev@openjdk.org" target="_blank">
<leyden-dev@openjdk.org></a><br>
<b>Sent: </b>Thursday, July 27, 2023 5:52:46 PM<br>
<b>Subject: </b>Draft JEP Announcement: "Computed Constants"<br>
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<span style="font-size:12pt;margin:0px;background-color:rgb(255,255,255)"><span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline">Hi
all,</span></span></div>
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<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> Maurizio and I have drafted a JEP for computed constants, which are</span><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> immutable value holders that are initialized at most once. They offer</span><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> the performance and safety benefits of final fields while offering</span><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> greater flexibility as to the timing of initialization. In the</span><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> context of Leyden, they could be one basis for shifting computation</span><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> both forward and backward in time.</span><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
<br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
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<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> The draft is here:</span><a href="https://openjdk.org/jeps/8312611" rel="noopener noreferrer" style="font-size:14.6667px;margin:0px;background-color:rgb(255,255,255)" target="_blank">https://openjdk.org/jeps/8312611</a><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
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<br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> Now that the Leyden repo is open, I’ll publish the prototype code to a</span><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> new branch there shortly.</span><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
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<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> Comments are welcome!</span><br style="font-size:14.6667px;color:rgb(36,36,36);background-color:rgb(255,255,255)">
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<span style="font-size:14.6667px;margin:0px;color:rgb(36,36,36);background-color:rgb(255,255,255);display:inline"> Best, Per</span></div>
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