Ruby and yield_self (next)

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One of the things that can make a series of operations on data more readable in code is using pipelines. In Elixir we will often use the pipe operator. In Ruby we will chain operations on collections together. For example:

(1..100_000)
  .map {|i| i * 3}
  .select {|i| i.odd?}
  .sum() 

Such pipelines could only be consructed using methods existing on the input of each stage. Ruby 2.5 introduced Object#yield_self, which makes the following possible.

"\ntmp/test.txt\n"
  .strip()
  .yield_self {|f| File.read(f)}

As yield_self is not the most intuitive of names, Ruby 2.6 will alias it to Object#then.

Acknowledgements

James Bell mentioned Object#yield_self and Object#then during the December 2018 ScotRUG meetup.