From: "stuyam (Stuart Yamartino) via ruby-core" <ruby-core@...>
Date: 2023-12-22T17:55:11+00:00
Subject: [ruby-core:115868] [Ruby master Feature#20080] Implement #begin_and_end method on Range

Issue #20080 has been updated by stuyam (Stuart Yamartino).


@ufuk I like `#bounds` as a name also, great suggestion, let's try that.

@Dan0042 Sorry for the bad example, I didn't show a good use case I just showed show I thought it would work. Here are a few use cases:

Use Case 1: Query filter, array deconstruction example
```ruby
def filter_by_date_range(date_range)
  start_date, end_date = date_range.bounds
  where('start > ? AND end < ?', start_date, end_date)
end
```
(I know rails supports ranges in ActiveRecord but I have needed this for more manual queries)

Use Case 2. Serialize a range to store as an array in a database column:
```ruby
# assumes a table with a `range_column` of type jsonb[] (array)
def store_in_table
  SomeTable.insert('range_column', range.bounds)
end
```

Use Case 3: Convert array of ranges to array of array bounds:
```ruby
range_array = [(1..10), (10..20), (20..30)]
bounds_array = range_array.map(&:bounds) #=> [[1, 10], [10, 20], [20, 30]]
```

Up until now you can only every "deserialize" the data out of a range into other parts using `#begin` and `#end` but have never been able to do it in one go. Sometimes you want just one value but often you want both. Often a range is passes between methods to keep the data as a single object especially if they are contextual to each other. For example, rather than passing around `start_date` and `end_date` as method params through a bunch of methods, you can just pass around a `date_range`. But in that case the range is just a way of keeping those values logically together. Or if one is nil such as a beginless or endless range it is more clear when they are kept together. In the end though, the `start_date` and `end_date` can be easily pulled out using array deconstruction with the `#bounds` method.

----------------------------------------
Feature #20080: Implement #begin_and_end method on Range
https://bugs.ruby-lang.org/issues/20080#change-105825

* Author: stuyam (Stuart Yamartino)
* Status: Open
* Priority: Normal
----------------------------------------
Followup Reference: #20027 

This feature request is to implement a method called `#begin_and_end` on `Range` that returns an array of the first and last value stored in a range:
```ruby
(1..300).begin_and_end #=> [1, 300]

first, last = (300..1).begin_and_end
first #=> 300
last #=> 1
```
I believe this would be a great addition to Ranges as they are often used to pass around a single object used to hold endpoints, and this allows easier retrieval of those endpoints.
This would allow easier deconstruction into start and end values using array deconstruction as well as a simpler way to serialize to a more primitive object such as an array for database storage.
This implementation was suggested by @mame in my initial feature suggestion regarding range deconstruction: https://bugs.ruby-lang.org/issues/20027

This implementation would work similar to how `#minmax` works where it returns an array of two numbers, however the difference is that `#minmax` doesn't work with reverse ranges as @Dan0042 pointed out in the link above:
```ruby
(1..42).minmax #=> [1, 42]
(42..1).minmax #=> [nil, nil]
```





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