<div dir="ltr">What if we could use the compiler to help ?<div><br></div><div>super(#args) </div><div><br></div><div>#args being the arguments passed to the current function.</div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr">
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<br><div class="gmail_quote">On Tue, Feb 9, 2016 at 9:09 AM, Radosław Pietruszewski <span dir="ltr"><<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><span class=""><div><blockquote type="cite"><div style="word-wrap:break-word">`super` would only exhibit the proposed behavior when it is a standalone token. The expressions `super` and `super.widgetCount` are both permitted and both are exactly equivalent.<div><br></div><div>To express what you're suggesting with the extension (either with the current grammar or the proposed feature), it would be:</div><div><br></div><div><font face="Courier New">override var widgetCount: Int {</font></div><div><font face="Courier New"> return super.widgetCount.widgetCount + 5</font></div><div><font face="Courier New">}</font></div><div><br></div><div>Your example is not ambiguous because `super.widgetCount` only ever means the value of the widgetCount property in the superclass; `super` is not first evaluated to the aforementioned value and then `widgetCount` invoked on that result, since the entire `super.widgetCount` would be treated atomically, conceptually, as it is now.</div></div></blockquote><br></div></span><div>Maybe, but I don’t like it. Even if the compiler can disambiguate, this will still be confusing.</div><span class=""><div><br></div><div><blockquote type="cite">Without offering an opinion either way on this proposal, I will note that the alternative suggestion of `super()` does not suffer from this ambiguity.</blockquote></div><div><br></div></span><div>You’re right! I’d be cool with `super()`.</div><br><div>
<div>— Radek</div>
</div><div><div class="h5">
<br><div><blockquote type="cite"><div>On 09 Feb 2016, at 09:44, Petroules Jake <<a href="mailto:Jake.Petroules@theqtcompany.com" target="_blank">Jake.Petroules@theqtcompany.com</a>> wrote:</div><br><div>
<div style="word-wrap:break-word">
`super` would only exhibit the proposed behavior when it is a standalone token. The expressions `super` and `super.widgetCount` are both permitted and both are exactly equivalent.
<div><br>
</div>
<div>To express what you're suggesting with the extension (either with the current grammar or the proposed feature), it would be:</div>
<div><br>
</div>
<div><font face="Courier New">override var widgetCount: Int {</font></div>
<div><font face="Courier New"> return super.widgetCount.widgetCount + 5</font></div>
<div><font face="Courier New">}</font></div>
<div><br>
</div>
<div>Your example is not ambiguous because `super.widgetCount` only ever means the value of the widgetCount property in the superclass; `super` is not first evaluated to the aforementioned value and then `widgetCount` invoked on that result, since
the entire `super.widgetCount` would be treated atomically, conceptually, as it is now.</div>
<div><br>
</div>
<div>I can see that the fact that `super` itself does refer to an instance of T could be problematic for properties. For functions, if written as `super()` or `super(...)` so this should be OK and unambiguous. Perhaps the shorthand syntax could be
limited to functions since they tend to be longer and in greater need of something like this in the first place.</div>
<div>
<div><br>
<div>
<blockquote type="cite">
<div>On Feb 9, 2016, at 12:28 AM, Radosław Pietruszewski <<a href="mailto:radexpl@gmail.com" target="_blank">radexpl@gmail.com</a>> wrote:</div>
<br>
<div>
<div style="word-wrap:break-word">
<div>I want to say +1.</div>
<div><br>
</div>
<div>Ruby does this and it works really nicely. While not a big deal in simple cases, when a method has lots of arguments, it’s just really noisy.</div>
<div><br>
</div>
<div>There’s a problem though. If `super` means both “call the superclass’s implementation of this method”, and “the superclass”, there’s a potential for ambiguity.</div>
<div><br>
</div>
<div>Say:</div>
<div><br>
</div>
<div>
<blockquote type="cite">
<div style="word-wrap:break-word">
<div>
<div>
<div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(187,44,162)">override</span> <span style="color:rgb(187,44,162)">var</span> widgetCount: <span style="color:rgb(112,61,170)">Int</span> {</div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(187,44,162)">return</span> <span style="color:rgb(187,44,162)">super</span>.widgetCount + <span style="color:rgb(39,42,216)">5</span></div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
}</div>
</div>
</div>
</div>
</div>
</blockquote>
<br>
</div>
<div>And:</div>
<div><br>
</div>
<blockquote style="margin:0 0 0 40px;border:none;padding:0px">
<div>extension Int {</div>
<div> var widgetCount: Int { return 10 }</div>
<div>}</div>
</blockquote>
<div><br>
</div>
<div>Does <span style="font-family:Menlo;font-size:11px;color:rgb(187,44,162)">super</span><span style="font-family:Menlo;font-size:11px">.widgetCount</span> call the superclass’s `widgetCount`, or does it call the superclass’s
implementation of the same getter, then call `widgetCount` on the returned Int?</div>
<br>
<div>
<div>— Radek</div>
</div>
<br>
<div>
<blockquote type="cite">
<div>On 09 Feb 2016, at 06:31, Petroules Jake via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>> wrote:</div>
<br>
<div>
<div style="word-wrap:break-word">
Hello,
<div><br>
</div>
<div>I have a language syntax proposal. I've read the Swift evolution guidelines and hopefully this is the proper way to start. So, my proposal is:</div>
<div><br>
</div>
<div>Permit a shorthand syntax for invoking the supertype implementation of a property or function. A single statement 'super' is equivalent to invoking the supertype implementation, forwarding the arguments unchanged, and returning the result. For
example, the following samples:</div>
<div><br>
</div>
<div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(187,44,162)">override</span> <span style="color:rgb(187,44,162)">func</span> mouseEntered(theEvent: <span style="color:rgb(112,61,170)">NSEvent</span>) {</div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(187,44,162)">super</span></div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(49,89,93)">handleMouseEvent</span>(theEvent)</div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
}</div>
</div>
<div><br>
</div>
<div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<div style="margin:0px;line-height:normal"><span style="color:rgb(187,44,162)">override</span> <span style="color:rgb(187,44,162)">func</span> specialValue(key: <span style="color:rgb(112,61,170)">String</span>)
-> <span style="color:rgb(112,61,170)">Int</span> {</div>
<div style="margin:0px;line-height:normal;color:rgb(187,44,162)">
<span> </span>return<span> </span>super<span> + </span><span style="color:rgb(39,42,216)">1</span></div>
<div style="margin:0px;line-height:normal">}</div>
<div style="margin:0px;line-height:normal"><br>
</div>
<div style="margin:0px;line-height:normal">
<div style="margin:0px;line-height:normal"><span style="color:rgb(187,44,162)">override</span> <span style="color:rgb(187,44,162)">var</span> widgetCount: <span style="color:rgb(112,61,170)">Int</span> {</div>
<div style="margin:0px;line-height:normal;color:rgb(187,44,162)">
<span> </span>return<span> </span>super<span> + </span><span style="color:rgb(39,42,216)">5</span></div>
<div style="margin:0px;line-height:normal">}</div>
</div>
</div>
</div>
<div><br>
</div>
<div>are exactly equivalent to the following samples:</div>
<div><br>
</div>
<div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(187,44,162)">override</span> <span style="color:rgb(187,44,162)">func</span> mouseEntered(theEvent: <span style="color:rgb(112,61,170)">NSEvent</span>) {</div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(187,44,162)">super</span>.<span style="color:rgb(61,29,129)">mouseEntered</span>(theEvent)</div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(49,89,93)">handleMouseEvent</span>(theEvent)</div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
}</div>
<div>
<div><br>
</div>
<div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<div style="margin:0px;line-height:normal"><span style="color:rgb(187,44,162)">override</span> <span style="color:rgb(187,44,162)">func</span> specialValue(key: <span style="color:rgb(112,61,170)">String</span>)
-> <span style="color:rgb(112,61,170)">Int</span> {</div>
<div style="margin:0px;line-height:normal"> <span style="color:rgb(187,44,162)">return</span> <span style="color:rgb(187,44,162)">super</span>.specialValue(key) + <span style="color:rgb(39,42,216)">1</span></div>
<div style="margin:0px;line-height:normal">}</div>
</div>
</div>
<div><br>
</div>
<div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(187,44,162)">override</span> <span style="color:rgb(187,44,162)">var</span> widgetCount: <span style="color:rgb(112,61,170)">Int</span> {</div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
<span style="color:rgb(187,44,162)">return</span> <span style="color:rgb(187,44,162)">super</span>.widgetCount + <span style="color:rgb(39,42,216)">5</span></div>
<div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo">
}</div>
</div>
<div><br>
</div>
<div>Alternatives/complementary ideas:</div>
<div><br>
</div>
<div>- Require `<span style="color:rgb(187,44,162);font-family:Menlo;font-size:11px">super</span><span style="font-family:Menlo;font-size:11px">()</span>` or `<span style="color:rgb(187,44,162);font-family:Menlo;font-size:11px">super</span><span style="font-family:Menlo;font-size:11px">(...)</span>`
syntax for invocations which are function calls, for consistency with other function calls in the language and/or to indicate that arguments are forwarded</div>
<div><br>
</div>
<div>Looking forward to your feedback.</div>
<div><br>
</div>
<div>Thanks!</div>
</div>
</div>
<div>
<div style="letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word">
<div style="letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word">
-- <br>
Jake Petroules - <a href="mailto:jake.petroules@theqtcompany.com" target="_blank">jake.petroules@theqtcompany.com</a><br>
Consulting Services Engineer - The Qt Company</div>
</div>
</div>
<br>
</div>
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</div>
</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
</div>
<br>
<div>
<div style="letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word">
<div style="letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word">
-- <br>
Jake Petroules - <a href="mailto:jake.petroules@theqtcompany.com" target="_blank">jake.petroules@theqtcompany.com</a><br>
Consulting Services Engineer - The Qt Company</div>
</div>
</div>
<br>
</div>
</div>
</div>
</div></blockquote></div><br></div></div></div><br>_______________________________________________<br>
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<br></blockquote></div><br></div>