ruby: Syntax for implicit block arguments

In a ruby block (or proc) you can implicitly refer to unnamed positional arguments with the special syntax \_1, \_2 etc.

[1,2,3].map { _1 + 1 }

Since ruby 3.4 you can implicitly refer to a single unnamed position argument with the special syntax it:

[1,2,3].map { it + 1 }