[ruby-core:78414] [Ruby trunk Feature#12786] String#casecmp?

Issue #12786 has been updated by Martin Dürst.


Ryan Ringler wrote:

> I see the changeset implements the new method by calling `String#downcase` on both strings and compares the results for equality.

Yes, this is as proposed at https://bugs.ruby-lang.org/issues/12786#note-1.

> While this does allow unicode support in advance of `String#casecmp`, it sacrifices the performance of character-by-character comparison that `#casecmp` provides.

Yes, I realized this as I implemented it. For the moment, my take is "better slow than fast and wrong".

> It's also going to lead to some inconsistent behavior:
> 
> ```
> 'äöü'.casecmp('ÄÖÜ').zero? # false
> 'äöü'.casecmp?('ÄÖÜ')      # true
> ```

Yes. I added some additional explanations to the documentation today to make this clearer.

> I hope this was considered, and perhaps when `String#casecmp` provides better support for unicode we can update `#casecmp?` to use it.

It would definitely be great to implement Unicode sorting, and in that case, we will make sure that casecmp and casecmp? are consistent again. But that will be a LOT of work. Also, please note that implementing Unicode sorting will make casecmp slower, too.



----------------------------------------
Feature #12786: String#casecmp?
https://bugs.ruby-lang.org/issues/12786#change-61787

* Author: Ryan Ringler
* Status: Closed
* Priority: Normal
* Assignee: Martin Dürst
----------------------------------------
Description

I would find String#casecmp? convenience method handy.  I don't believe I've ever called String#casecmp without chaining #zero? to the result.

```ruby
'abc'.casecmp?('ABC') #=> true
'abc'.casecmp?('DEF') #=> false
```

---Files--------------------------------
string_casecmp_.patch (4.97 KB)


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