From: zverok.offline@...
Date: 2018-01-24T14:43:40+00:00
Subject: [ruby-core:85051] [Ruby trunk Feature#14392] Pipe operator

Issue #14392 has been updated by zverok (Victor Shepelev).


We already have `yield_self` (2.5+) exactly for this. 

```ruby
class Foo

  ##
  # Bar public method.

  def bar(*args)
    args.select do { |arg| arg =~ /regex/ }.first
      yield_self(&method(:good))
  end.yield_self(&method(:public))

  def good(arg)
    arg.to_s.size > 10
  end.yield_self(&method(:private))
end

# Though this method of publicize and privatize seem... well, less-than-optimal for me, pipe or yield_self
```

While introducing it, different alternatives have been discussed, including Elixir-like operator, and rejected.

----------------------------------------
Feature #14392: Pipe operator
https://bugs.ruby-lang.org/issues/14392#change-69769

* Author: dsferreira (Daniel Ferreira)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I would like to see implemented in ruby a pipe operator as we have in elixir.

An example of application I have in mind is this:

```ruby
class Foo

  def bar(var)
    puts ���Hello #{var}!���
  end |> private
  
  def baz(arg)
    bar(arg)
  end 
 
end

foo = Foo.new
foo.baz("Fred") # => "Hello Fred!"
```

It can also help simplify method chains:

```ruby
class Secret

  def initialise(user, password)
    @user = user
    @password = password
  end

  def second_pass(encrypted_string)
    encrypted_string.chain_4.chain_5.chain_6
  end |> private

  ##
  #  Super encryption

  def super_encryption
    @password.chain_1.chain_2.chain_3
      |> second_pass
  end |> public

end
```

And also simplify codes like this:

```ruby
class Foo

  def bar(*args)
    baz = args.select { |arg| arg =~ /regex/ }.first
    good?(baz)
  end

  public :bar

  def good(arg)
    arg.to_s.size > 10
  end
  
  private :good

end
```

to become:

```ruby
class Foo

  ##
  # Bar public method.

  def bar(*args)
    args.select { |arg| arg =~ /regex/ }.first
      |> good?
  end |> public

  def good(arg)
    arg.to_s.size > 10
  end |> private

end
```

Lots of local variables would be saved and I would expect some performance improvements with that.



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