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> <span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">So do I have everyone's consent in changing trunk over to read-only literals? If there are no strenuous complaints by tomorrow noon, PST, I shall effect the change.</span><div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px"><br></span></div><div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">+1 :-)</span></div><div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px"><br></span></div><div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">Best,</span></div><div><span style="font-family: Arial, Helvetica, sans-serif;font-size: 13px">Marcel</span></div><div class="mb_sig"></div><blockquote class="history_container" type="cite" style="border-left-style:solid;border-width:1px; margin-top:20px; margin-left:0px;padding-left:10px;">
<p style="color: #AAAAAA; margin-top: 10px;">Am 11.03.2020 22:10:56 schrieb Eliot Miranda <eliot.miranda@gmail.com>:</p><div style="font-family:Arial,Helvetica,sans-serif">
<div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr">Hi All,<div><br></div><div> I'v committed the core support for read-only objects, adapted from Clément's Pharo implementation. Enabling read-only literals is a very small step from that (three methods modified in the parser, and one method modified in Symbol class). I would like to do this as soon as possible, but it may break code. Hence my asking for permission/sending out a warning before hand. Note that the only code it will break is bad code; code that writes to literals.</div><div><br></div><div>With the changes installed doing this:</div><div><br></div><div>#(1 2 3) at: 2 put: 'nevermore'<br></div><div><br></div><div>raises a ModificationForbidden exception with the message text "ModificationForbidden: #(1 2 3) is read-only, hence its field 2 cannot be modified with 'nevermore'"</div><div><br></div><div><br></div><div>When we added read-only object support to VisualWorks some of the engineering staff were of the opinion that insulating customers from the change was a necessary thing, and so we implemented a preference to allow automatic mutating of read-only literals so that customers whose code did modify literals could set the preference rather than fix their code. I *really* don't ant to do this. It is a lot of complication for little gain; the right fix is just to rewrite the code not to write to literals. Note that that's as easy as:</div><div><br></div><div>#(1 2 3) copy at: 2 put: 'nevermore'; yourself</div><div>=></div><div><div>#(1 'nevermore' 3)</div></div><div><br></div><div>since copies of read-only objects are mutable.</div><div><br></div><div>So do I have everyone's consent in changing trunk over to read-only literals? If there are no strenuous complaints by tomorrow noon, PST, I shall effect the change.</div><div><br></div><div>To avoid recompiling (which can produce unbound methods, etc) I shall change literals to be read-only via a pass over all literals and a pass over the Symbol table. Hence the change should be non-invasive. If your code (like probably 99.9% of all code in the system) doesn't write to literals you won't notice.</div><div><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><span style="font-size: 10pt;border-collapse: separate"><div>_,,,^..^,,,_<br></div><div>best, Eliot</div></span></div></div></div></div></div></div></div></div></div>
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