From: tagomoris@...
Date: 2017-09-20T10:41:31+00:00
Subject: [ruby-core:82894] [Ruby trunk Feature#13923] Idiom to release resources safely, with less indentations

Issue #13923 has been updated by tagomoris (Satoshi TAGOMORI).


nobu (Nobuyoshi Nakada) wrote:
> Probably a way which is close to it right now would be:
> 
> ```ruby
> begin
>   storage = getStorage()
>   buffer = storage.get(buffer_id)
> 
>   # ...
> rescue StorageError => e
>   # ...
> ensure
>   buffer&.close
>   storage&.close
> end
> ```

With this code, storage will not be closed if `buffer.close` raises exceptions.

----------------------------------------
Feature #13923: Idiom to release resources safely, with less indentations
https://bugs.ruby-lang.org/issues/13923#change-66793

* Author: tagomoris (Satoshi TAGOMORI)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
In programs which grabs and releases resources very often, we need to write so much begin-ensure clauses.

```ruby
begin
  storage = getStorage()
  begin
    buffer = storage.get(buffer_id)

    # ...
  ensure
    buffer.close if buffer
  end
rescue StorageError => e
  # ...
ensure
  storage.close if storage
end
```

Such code makes our code fat, and difficult to understand.
I want to write such code like below:

```ruby
# Class of storage and buffer should include a module (like Closeable)
# or be checked with respond_to?(:close)

begin(storage = getStorage(); buffer = storage.get(buffer_id)
  # ...
rescue StorageError => e
  # ...
end
# (buffer.close if buffer) rescue nil
# (storage.close if storage) rescue nil
```

Other languages also have similar features:

* Java: try-with-resources
* Python: with




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