[ruby-core:110767] [Ruby master Misc#19131] MatchData#values_at(): addressing with Range and Integer index behaves differently for the first element (entire matched string)

[ruby-core:110767] [Ruby master Misc#19131] MatchData#values_at(): addressing with Range and Integer index behaves differently for the first element (entire matched string)

[andrykonchin (Andrew Konchin)]

Issue #19131 has been reported by andrykonchin (Andrew Konchin).

----------------------------------------
Misc #19131: MatchData#values_at(): addressing with Range and Integer index behaves differently for the first element (entire matched string)
https://bugs.ruby-lang.org/issues/19131

* Author: andrykonchin (Andrew Konchin)
* Status: Open
* Priority: Normal
----------------------------------------
I've noticed a strange nuance and not sure whether it's intentional or not. In case it's intentional - it seems to me inconsistent.

I will illustrate it with the following example:

```ruby
/(.)(.)(.)(.)/.match("abcde").values_at(-5..-1) # => ["abcd", "a", "b", "c", "d"]
/(.)(.)(.)(.)/.match("abcde").values_at(-5) # => [nil]
```

So with a negative index we can address the whole matched string (`0` element) with a Range argument but cannot with an Integer index.

We can index with negative values only captured values:

```ruby
/(.)(.)(.)(.)/.match("abcde").values_at(-4) # => ["a"]
/(.)(.)(.)(.)/.match("abcde").values_at(-3) # => ["b"]
/(.)(.)(.)(.)/.match("abcde").values_at(-2) # => ["c"]
# ...
```

---

```
ruby -v
ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-darwin21]
```



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