[ruby-core:96590] [Ruby master Misc#16464] Which core objects should support deconstruct/deconstruct_keys?

Issue #16464 has been updated by decuplet (Nikita Shilnikov).


These probably should be filed as separate feature requests. I'm already using PM in production and the idea about deconstructing `Time` instances also came into my mind. `Object#deconstruct` is a lot more subtle, I wouldn't say it's _that_ obvious, I'd rather have it for some built-in classes such as `Time` or `Integer`.

----------------------------------------
Misc #16464: Which core objects should support deconstruct/deconstruct_keys?
https://bugs.ruby-lang.org/issues/16464#change-83557

* Author: zverok (Victor Shepelev)
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
Now, when pattern matching is out, I believe it is worth discussing which core and standard library objects should be matchable "out of the box".

My proposals, as of now, are:

**1. `Object#deconstruct`, returning `[self]`.**

Justification:
```ruby
# this works:
1 in Integer
# this works:
1 in ..0
# this does NOT:
1 in Integer(..0)
# NoMatchingPatternError (1)
```
I believe the latter example looks pretty logical (and can be used in some flexible methods like "if it is a positive integer, it is index in the array, if it is negative integer, it is backward index, and if it is float, it should be calculated as a mean of nearby elements")

**2. `Time#deconstruct_keys`**

Justification is obvious:

```ruby
case created_at
when year: 2019, month: 11..12 => m, day:
  p "Created at #{day}.#{m} this year"
else
  # ...
end
```
(Probably the same for `Date` and `DateTime`)

**3. `Set#deconstruct`**

Seems "logical" as set is a sequence, but I can't think of a good realistic example :)



-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:[e-mail]?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>