From: Joseph Jones <joeyi5216@...>
Date: 2015-12-17T21:07:04-07:00
Subject: [ruby-core:72295] [Ruby trunk - Bug #11816] [Open] Partial safe navigation operator

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Joseph Jones liked your message with Boxer. On December 14, 2015 at 11:19=
:37 MST, ruby-core=40marc-andre.ca wrote:Issue =2311816 has been reported=
 by Marc-Andre Lafortune.----------------------------------------Bug =231=
1816: Partial safe navigation operatorhttps://bugs.ruby-lang.org/issues/1=
1816* Author: Marc-Andre Lafortune* Status: Open* Priority: Normal* Assig=
nee: Yukihiro Matsumoto* ruby -v: preview 2* Backport: 2.0.0: UNKNOWN, 2.=
1: UNKNOWN, 2.2: UNKNOWN----------------------------------------I'm extre=
mely surprised (and disappointed) that, currently: x =3D nil x&.foo.bar =23=
 =3D> NoMethodError: undefined method =60bar' for nil:NilClassTo make it =
safe, you have to write =60x&.foo&.bar=60. But if =60foo=60 is never supp=
osed to return =60nil=60, then that code isn't =22fail early=22 in case i=
t actually does. =60nil&.foo.bar=60 is more expressive, simpler and is pe=
rfect if you want to an error if =60foo=60 returned =60nil=60. To actuall=
y get what you want, you have to resort using the old form =60x && x.foo.=
bar=60...In CoffeeScript, you can write =60x()=3F.foo.bar=60 and it will =
work well, since it gets compiled to if ((=5Fref =3D x()) =21=3D null) =7B=
 =5Fref.foo.bar; =7DAll the discussion in =2311537 focuses on =60x&.foo&.=
bar=60, so I have to ask:Matz, what is your understanding of =60x&.foo.ba=
r=60=3FI feel the current implementation is not useful and should be chan=
ged to what I had in mind. I can't see any legitimate use of =60x&.foo.ba=
r=60 currently.-- https://bugs.ruby-lang.org/     
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<html><body><div>Joseph Jones liked your message with <a href=3D=22http:/=
/bxr.io/PBIqo=22>Boxer</a>.</div><br/><br/><div><div class=3D=22quote=22>=
On December 14, 2015 at 11:19:37 MST, ruby-core=40marc-andre.ca wrote:<br=
/><blockquote type=3D=22cite=22 style=3D=22border-left-style:solid;border=
-width:1px;margin-left:0px;padding-left:10px;=22>Issue =2311816 has been =
reported by Marc-Andre Lafortune.<br /><br />----------------------------=
------------<br />Bug =2311816: Partial safe navigation operator<br />htt=
ps://bugs.ruby-lang.org/issues/11816<br /><br />* Author: Marc-Andre Lafo=
rtune<br />* Status: Open<br />* Priority: Normal<br />* Assignee: Yukihi=
ro Matsumoto<br />* ruby -v: preview 2<br />* Backport: 2.0.0: UNKNOWN, 2=
.1: UNKNOWN, 2.2: UNKNOWN<br />----------------------------------------<b=
r />I'm extremely surprised (and disappointed) that, currently:<br /><br =
/>    x =3D nil<br />    x&.foo.bar =23 =3D> NoMethodError: undefined met=
hod =60bar' for nil:NilClass<br /><br />To make it safe, you have to writ=
e =60x&.foo&.bar=60. But if =60foo=60 is never supposed to return =60nil=60=
, then that code isn't =22fail early=22 in case it actually does. =60nil&=
.foo.bar=60 is more expressive, simpler and is perfect if you want to an =
error if =60foo=60 returned =60nil=60. To actually get what you want, you=
 have to resort using the old form =60x && x.foo.bar=60...<br /><br />In =
CoffeeScript, you can write =60x()=3F.foo.bar=60 and it will work well, s=
ince it gets compiled to<br /><br />    if ((=5Fref =3D x()) =21=3D null)=
 =7B<br />      =5Fref.foo.bar;<br />    =7D<br /><br />All the discussio=
n in =2311537 focuses on =60x&.foo&.bar=60, so I have to ask:<br /><br />=
Matz, what is your understanding of =60x&.foo.bar=60=3F<br /><br />I feel=
 the current implementation is not useful and should be changed to what I=
 had in mind. I can't see any legitimate use of =60x&.foo.bar=60 currentl=
y.<br /><br /><br /><br /><br />-- <br />https://bugs.ruby-lang.org/<br /=
></blockquote></div></div></body></html>
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