From: shyouhei@... Date: 2016-03-17T06:34:06+00:00 Subject: [ruby-core:74397] [Ruby trunk Bug#11816] Partial safe navigation operator Issue #11816 has been updated by Shyouhei Urabe. I was not active when this topic was hot, so to know the current status I asked this on this month's developer meeting. The bottom line is there was no concrete answer for this issue yet. At first "propagating &. as long as explicit method chain continues" seemed to be the right way. But we found there still are edge cases that should be clearly described before adopting that way. Consider: ~~~ruby a&.b.c += d ~~~ here, if it was `a.b.c += d`, it calls two methods `a.b.c` and `a.b.c=`. Then what should happen for `&.` ? ---------------------------------------- Bug #11816: Partial safe navigation operator https://bugs.ruby-lang.org/issues/11816#change-57518 * Author: Marc-Andre Lafortune * Status: Open * Priority: Normal * Assignee: Yukihiro Matsumoto * ruby -v: preview 2 * Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN ---------------------------------------- I'm extremely surprised (and disappointed) that, currently: x = nil x&.foo.bar # => NoMethodError: undefined method `bar' for nil:NilClass To make it safe, you have to write `x&.foo&.bar`. But if `foo` is never supposed to return `nil`, then that code isn't "fail early" in case it actually does. `nil&.foo.bar` is more expressive, simpler and is perfect if you want to an error if `foo` returned `nil`. To actually get what you want, you have to resort using the old form `x && x.foo.bar`... In CoffeeScript, you can write `x()?.foo.bar` and it will work well, since it gets compiled to if ((_ref = x()) != null) { _ref.foo.bar; } All the discussion in #11537 focuses on `x&.foo&.bar`, so I have to ask: Matz, what is your understanding of `x&.foo.bar`? 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 `x&.foo.bar` currently. -- https://bugs.ruby-lang.org/ Unsubscribe: