From: lpogic via ruby-core <ruby-core@...>
Date: 2024-11-09T11:37:04+00:00
Subject: [ruby-core:119863] [Ruby master Feature#20770] A *new* pipe operator proposal

Issue #20770 has been updated by lpogic (��ukasz Pomiet��o).


austin (Austin Ziegler) wrote in #note-40:
> Ruby already *has*  pipeline-like method, `#then`. If `|>` or `.{}` acts as syntactic sugar for `#then`, I don't see an issue here. If, internally, it���s turned into the effective equivalent of `__pipe1 = r; __pipe2 = q(__pipe1); __pipe3 = p(__pipe2); __pipe3`, I don't see an issue here. But under no circumstances do I think that the effective temporary assignments should be exposed or made available to method calls further down the pipeline or after the pipeline is complete. That's too much magic.

Can't the "|>" operator also be considered a cousin of "&&", which is unconditional but passes the LHS result?
``` ruby
p1 = (rr = r) |>       q( _)  |> p( _, rr)
p2 = (rr = r) && (qr = q(rr)) && p(qr, rr) 
p1 == p2 # true if r(), q(), p() never return false/nil
```





----------------------------------------
Feature #20770: A *new* pipe operator proposal
https://bugs.ruby-lang.org/issues/20770#change-110553

* 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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