From: "AlexandreMagro (Alexandre Magro) via ruby-core" <ruby-core@...>
Date: 2024-10-01T13:08:04+00:00
Subject: [ruby-core:119381] [Ruby master Feature#20770] A *new* pipe operator proposal

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


vo.x (Vit Ondruch) wrote in #note-18:
> Right, this was far fetched and would not work admittedly. But that is why I proposed the `client_api_url.to(URI)`, because after all, this is IMHO mostly about type conversion. Why would I ever want to call something like `URI.parse(it)`? Why would I need to know there is `parse` method and why would I need to put `it` / `_1` multiple times everywhere and every time in different context.

Zverok was precise in his comment.

I understand your point, but the idea of to(URI) introduces an inversion of responsibility, which can lead to dependency inversion issues ��� a poor practice in software design, especially when working with different libraries.

It's unclear what you mean by `client_api_url` in this context since, in my example, it was simply a string. Having a .to method on a string seems generic and nonsensical.

As for the question "Why would I ever want to call something like URI.parse(it)?", code is already written this way. The pipe operator doesn���t change the syntax but rather inverts the reading flow.

Lastly, the pipe operator is a well-established concept that aims to streamline existing Ruby syntax, not alter it.

```ruby
client_api_url
  |> URI.parse(it)
  |> Net::HTTP.get(it)
  |> JSON.parse(it).fetch(important_key)
```

This is so clean. It's just Ruby.

----------------------------------------
Feature #20770: A *new* pipe operator proposal
https://bugs.ruby-lang.org/issues/20770#change-109998

* 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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