[ruby-core:93135] [Ruby trunk Feature#15799] pipeline operator

[mail@tinco.nl]

Issue #15799 has been updated by d-snp (Tinco Andringa).


From my perspective, the |> operator exists because in functional programming languages you have these increasingly nested function calls which have to end with a stack of parentheses that are hard to read. In Haskell I very frequently use the $ operator for a similar effect. In Ruby this problem is not significant at all, it almost never happens that we have nested parentheses, and in the case we do (like calling methods inside method parameters) the pipeline operator wouldn't be a solution anyway.

I think it's not good to introduce a new operator just for a rare use case that isn't idiomatic Ruby. 

If my employees wrote

```
 a |> method1 b |> method2 c
```

I would correct them that the code could be simplified to

```
a.method1(b).method2(c)
```

Not the other way around.

It's not even very common for Ruby methods to return self.

----------------------------------------
Feature #15799: pipeline operator
https://bugs.ruby-lang.org/issues/15799#change-78564

* Author: nobu (Nobuyoshi Nakada)
* Status: Closed
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
Implemented the pipeline operator `|>`, a topic of "ruby committers vs the world" in RubyKaigi 2019.
Also a casual idea of rightward assignment.

```ruby
1.. |> take 10 |> map {|e| e*2} |> (x)
p x #=> [2, 4, 6, 8, 10, 12, 14, 16, 18, 20]
```

https://github.com/nobu/ruby/tree/feature/pipeline




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