From: lpogic via ruby-core <ruby-core@...>
Date: 2024-10-03T21:55:16+00:00
Subject: [ruby-core:119436] [Ruby master Feature#20770] A *new* pipe operator proposal

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


Has 'then' but as a keyword been considered? 
In the basic version it could appear as a 'begin..then..end' block:
``` ruby
value = begin add value, 3 then square it then half it end
```
It looks like syntax highlighting is ready. 'begin' can be replaced with something else, but then it would be harder to prove such forms:
``` ruby
value = begin value
then add it, 3
then square it
then |v| # optional 'it' name?
  half v
rescue # optional error handling?
  puts "Error"
  0
end
```

``` ruby
def foo(value)
  add value, 3
then
  square it
then
  half it
end
```
The endless (and beginless) version may be more controversial, but if used with caution it could make sense:
``` ruby
value = add value, 3 then square it then half it
```







----------------------------------------
Feature #20770: A *new* pipe operator proposal
https://bugs.ruby-lang.org/issues/20770#change-110056

* 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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