[#111472] [Ruby master Bug#19274] Error installing ruby 3.2.0 on RH 8 — "aalllop (Alberto Allegue) via ruby-core" <ruby-core@...>
Issue #19274 has been reported by aalllop (Alberto Allegue).
5 messages
2022/12/28
[#111508] Data support for versions before 3.2.0 — Eustáquio Rangel via ruby-core <ruby-core@...>
I was wondering that every piece of code (gems, etc) that use the new Data =
3 messages
2022/12/29
[ruby-core:111516] [Ruby master Bug#19278] Constructing subclasses of Data with positional arguments
From:
"zverok (Victor Shepelev) via ruby-core" <ruby-core@...>
Date:
2022-12-29 22:34:07 UTC
List:
ruby-core #111516
Issue #19278 has been updated by zverok (Victor Shepelev).
@sam.saffron your hand-maid `Foo` is analogous to `Foo = Data.define(:x)`, right?
Now, can you please show what if somebody wants to inherit your `Foo` to provide:
* argument conversion for `x`
* or, default value for `x`
I believe, the best you can get with would be something like this, for data conversion:
```ruby
UNDEFINED = Object.new.freeze
class MyFoo < Foo
def initialize(pos_x = UNDEFINED, x: UNDEFINED)
# 1. check that one, and exactly of them is `UNDEFINED`
# 2. do the conversion with the right one, we'd like to preserve the protocol, right?..
if pos_x == UNDEFINED
super(x: x.to_i)
else
super(pos_x.to_i)
end
end
end
```
Providing the default value, how would you address this?.. Please share your thoughts!
With the current protocol, it is just like that:
```ruby
# Conversion
Foo = Data.define(:x) do
def initialize(x:) = super(x: x.to_i)
end
# Default value:
Foo = Data.define(:x) do
def initialize(x: 0) = super
end
# Both with now work with Foo.new(1) and Foo.new(x: 1), without breaking the contract that Data promises
```
Yes, the rule "`Data#initialize` accepts only keyword arguments" is unlike the barest "simple class" implementation, but:
1. For a good reason
2. It is a rule consisting of _exactly one phrase_; even if one considers it "a dumb quirk," it is not something that is impossible to explain or remember
3. But it is not "a dumb quirk"
----------------------------------------
Bug #19278: Constructing subclasses of Data with positional arguments
https://bugs.ruby-lang.org/issues/19278#change-100884
* Author: tenderlovemaking (Aaron Patterson)
* Status: Feedback
* Priority: Normal
* ruby -v: ruby 3.2.0 (2022-12-25 revision a528908271) [arm64-darwin22]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN
----------------------------------------
I'd expect both of the following subclasses to work, but the subclass that uses positional parameters raises an exception:
```ruby
Foo = Data.define
class Bar < Foo
def initialize foo:
p foo
end
end
class Baz < Foo
def initialize foo
p foo
end
end
Bar.new foo: 1 # Prints 1
Baz.new 1 # Raises ArgumentError
```
I'd expect the subclass that uses positional arguments to work.
--
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