[ruby-core:75185] [Ruby trunk Feature#12318] Returning the evaluated value of a block

Issue #12318 has been updated by Nobuyoshi Nakada.


It doesn't seem generic enough to be defined in `Enumerator`.
The receiver enumerator may return different object than its elements nor the results of the given block, whereas that `and_return` has to manage the association of them.

Why not simpler:

```ruby
[7, 8, 9].map{|e| e % 3}.max
# => 2
```

```ruby
["foo", "bar", "baz"].find{|e| break e if e = e[/(.)\1/]}
# => "oo"
```

or

```ruby
["foo", "bar", "baz"].grep(/(.)\1/) {break $&}
# => "oo"
```

----------------------------------------
Feature #12318: Returning the evaluated value of a block
https://bugs.ruby-lang.org/issues/12318#change-58316

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
I often achieve an element using an iterator with a block, and then apply the same/a similar block to the element I get. Examples are:

~~~ruby
[7, 8, 9]
.max_by{|e| e % 3}
.tap{|e| break e % 3}
# => 2

["foo", "bar", "baz"]
.find{|e| e[/(.)\1/]}
.tap{|e| break e[/(.)\1/]}
# => "oo"
~~~

I would like a method on `Enumerator` that returns the result of the block rather than the original element in the iterator. Not sure about the name, but if I call it `and_return` temporary, it should look like:

~~~ruby
[7, 8, 9]
.max_by.and_return{|e| e % 3}
# => 2

["foo", "bar", "baz"]
.find.and_return{|e| e[/(.)\1/]}
# => "oo"
~~~




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