[#111712] [Ruby master Feature#19322] Support spawning "private" child processes — "kjtsanaktsidis (KJ Tsanaktsidis) via ruby-core" <ruby-core@...>
SXNzdWUgIzE5MzIyIGhhcyBiZWVuIHJlcG9ydGVkIGJ5IGtqdHNhbmFrdHNpZGlzIChLSiBUc2Fu
14 messages
2023/01/07
[ruby-core:112008] [Ruby master Feature#19236] Allow to create hashes with a specific capacity from Ruby
From:
"Eregon (Benoit Daloze) via ruby-core" <ruby-core@...>
Date:
2023-01-24 14:23:31 UTC
List:
ruby-core #112008
Issue #19236 has been updated by Eregon (Benoit Daloze).
If we use `Hash.new(capacity: 4096)` to set the capacity, then `Hash.new({ capacity: 4096 })` should keep the semantics of: `{ capacity: 4096 }` is the default value of the new Hash.
I think it's a little bit hacky/unclear/source of confusion, but still I'm not against it.
----------------------------------------
Feature #19236: Allow to create hashes with a specific capacity from Ruby
https://bugs.ruby-lang.org/issues/19236#change-101441
* Author: byroot (Jean Boussier)
* Status: Open
* Priority: Normal
* Target version: 3.3
----------------------------------------
Followup on [Feature #18683] which added a C-API for this purpose.
Various protocol parsers such as Redis `RESP3` or `msgpack`, have to create hashes, and they know the size in advance.
For efficiency, it would be preferable if they could directly allocate a Hash of the necessary size, so that large hashes wouldn't cause many re-alloccations and re-hash.
`String` and `Array` both already offer similar APIs:
```ruby
String.new(capacity: XXX)
Array.new(XX) / rb_ary_new_capa(long)
```
However there's no such public API for Hashes in Ruby land.
### Proposal
I think `Hash` should have a way to create a new hash with a `capacity` parameter.
The logical signature of `Hash.new(capacity: 1000)` was deemed too incompatible in [Feature #18683].
@Eregon proposed to add `Hash.create(capacity: 1000)`.
--
https://bugs.ruby-lang.org/
______________________________________________
ruby-core mailing list -- [email protected]
To unsubscribe send an email to [email protected]
ruby-core info -- https://ml.ruby-lang.org/mailman3/postorius/lists/ruby-core.ml.ruby-lang.org/
