From: "esad (Esad Hajdarevic) via ruby-core" <ruby-core@ml.ruby-lang.org>
To: ruby-core@ml.ruby-lang.org
Cc: "esad (Esad Hajdarevic)" <noreply@ruby-lang.org>
Subject: [ruby-core:117679] [Ruby master Feature#20444] Kernel#loop: returning the "result" value of StopIteration doesn't work when raised directly
Date: Wed, 24 Apr 2024 11:00:10 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-108089.20240424110010.53307@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-20444.20240422214119.53307@ruby-lang.org
Issue #20444 has been updated by esad (Esad Hajdarevic).
ufuk (Ufuk Kayserilioglu) wrote in #note-7:
> @esad If you just want to return a result from the `loop`, you can use `break <value>` to do that:
> ```
> $ ruby -e "puts loop { break 3 }"
> 3
Calling break from a block passed to a ractor will raise an exception. I think some sample code about my example will be helpful:
Let's make a ractor that just calls all blocks passed to it in a loop:
```
r = Ractor.new do
block = Ractor.receive
loop { block.call() }
end
```
Now let's send it a block that raises StopIteration:
```
block = true.instance_eval { proc { raise StopIteration, 3 } } # instance_eval in true gives us a "shareable" proc
r.send Ractor.make_shareable(block)
r.take # => nil
```
Let's try with a subclass (this works)
```
class MyStop < ::StopIteration
attr_reader :result
def initialize(result)
@result = result
end
end
block = true.instance_eval { proc { raise MyStop, 3 } }
r.send Ractor.make_shareable(block)
r.take # => 3
```
----------------------------------------
Feature #20444: Kernel#loop: returning the "result" value of StopIteration doesn't work when raised directly
https://bugs.ruby-lang.org/issues/20444#change-108089
* Author: esad (Esad Hajdarevic)
* Status: Feedback
----------------------------------------
There was a https://bugs.ruby-lang.org/issues/11498 a while ago which was merged in, but I was surprised to find out that raising `StopIteration` in a loop like
`loop { raise StopIteration.new(3) }`
returns nil and not 3.
--
https://bugs.ruby-lang.org/
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next prev parent reply other threads:[~2024-04-24 11:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-22 21:41 [ruby-core:117646] [Ruby master Bug#20444] Kernel#loop: returning the "result" value of StopIteration doesn't work when raised directly esad (Esad Hajdarevic) via ruby-core
2024-04-23 5:02 ` [ruby-core:117649] " nobu (Nobuyoshi Nakada) via ruby-core
2024-04-23 6:21 ` [ruby-core:117650] " esad (Esad Hajdarevic) via ruby-core
2024-04-24 2:40 ` [ruby-core:117667] " nobu (Nobuyoshi Nakada) via ruby-core
2024-04-24 9:07 ` [ruby-core:117673] [Ruby master Feature#20444] " esad (Esad Hajdarevic) via ruby-core
2024-04-24 10:40 ` [ruby-core:117678] " ufuk (Ufuk Kayserilioglu) via ruby-core
2024-04-24 11:00 ` esad (Esad Hajdarevic) via ruby-core [this message]
2024-04-26 8:28 ` [ruby-core:117722] " nobu (Nobuyoshi Nakada) via ruby-core
2024-04-26 10:07 ` [ruby-core:117726] " esad (Esad Hajdarevic) via ruby-core
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