[ruby-core:87257] [Ruby trunk Feature#14097] Add union and difference to Array

Issue #14097 has been updated by Student (Nathan Zook).


I cannot say that I am a fan of this proposal.  To be fair, I'm not a fan of #|.

Arrays are not sets.  Trying to treat them as if they are is an error, and will create subtle problems.

What should be the result of the following operations?
[1, 1] | [1]
[1] | [1, 1]

Of course, there are more interesting examples.  These two are to get you started.

I don't care what the results currently are.  I don't care what you think they should be.  I can present extremely strong arguments for various answers.  For this reason, I believe that #| is an ill-defined concept.

Generalizing an ill-defined concept is a world of pain.

If you insist on treating objects of one class as if they were members of a different class, there should be bumps in the road to at least warn you that maybe this is a bad idea.

I'm not going to argue that we should remove or deprecate #|.  I don't think of myself as a fanatic.  But encouraging this sort of abuse of the type system just creates problems.



----------------------------------------
Feature #14097: Add union and difference to Array
https://bugs.ruby-lang.org/issues/14097#change-72247

* Author: ana06 (Ana Maria Martinez Gomez)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
Currently there is a concat method in ruby which does the same as +, but modifying the object. We could introduce a union and difference methods, which would be the equivalent for the `|` and `-` operators. This operators are normally less used due to lack of readability and expressivity. You end seeing thinks like:

```
array.concat(array2).uniq!
```

just because it is more readable. When it could be written like:

```
array |= array2
```

But, as this is not clear for some people, the new method will solve this problem:

```
array.union(array2)
```

And now this is clean and readable, as everybody expect from Ruby, the language focused on simplicity and productivity. ;)


Can I send a PR? :)





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