From: "AlexandreMagro (Alexandre Magro) via ruby-core" <ruby-core@...>
Date: 2024-11-08T20:28:28+00:00
Subject: [ruby-core:119851] [Ruby master Feature#20770] A *new* pipe operator proposal

Issue #20770 has been updated by AlexandreMagro (Alexandre Magro).


@lpogic In these cases, you wouldn���t use pipes:

```ruby
def foo
  q_result = q(r) # because q_result is important and deserves its own variable
  
  p(r)

  q_result
end
```

The pipe operator is useful when you just need to nest method calls and aren���t interested in each individual value. Example:

```ruby
schema = JSON.parse(File.read(Rails.root.join(RELATIVE_PATH_TO_CONFIG)))

# becomes

schema = Rails.root.join(RELATIVE_PATH_TO_CONFIG) |> File.read _ |> JSON.parse _

# The same written with a .then chain

schema = Rails.root.join(RELATIVE_PATH_TO_CONFIG).then { File.read(_1) }.then { JSON.parse(_1) }
```

The point is that this shows the natural flow: "Concatenate this string, read the file with that name, and then parse the JSON."

----------------------------------------
Feature #20770: A *new* pipe operator proposal
https://bugs.ruby-lang.org/issues/20770#change-110542

* Author: AlexandreMagro (Alexandre Magro)
* Status: Open
----------------------------------------
Hello,

This is my first contribution here. I have seen previous discussions around introducing a pipe operator, but it seems the community didn't reach a consensus. I would like to revisit this idea with a simpler approach, more of a syntactic sugar that aligns with how other languages implement the pipe operator, but without making significant changes to Ruby's syntax.

Currently, we often write code like this:

```ruby
value = half(square(add(value, 3)))
```

We can achieve the same result using the `then` method:

```ruby
value = value.then { add(_1, 3) }.then { square(_1) }.then { half(_1) }
```

While `then` helps with readability, we can simplify it further using the proposed pipe operator:

```ruby
value = add(value, 3) |> square(_1) |> half(_1)
```

Moreover, with the upcoming `it` feature in Ruby 3.4 (#18980), the code could look even cleaner:

```ruby
value = add(value, 3) |> square(it) |> half(it)
```

This proposal uses the anonymous block argument `(_1)`, and with `it`, it simplifies the code without introducing complex syntax changes. It would allow us to achieve the same results as in other languages that support pipe operators, but in a way that feels natural to Ruby, using existing constructs like `then` underneath.

I believe this operator would enhance code readability and maintainability, especially in cases where multiple operations are chained together.

Thank you for considering this proposal!






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