Pipe Forward and Pipe Backward

The post revisits F# pipe operators and notes that pipe-forward is used more often than pipe-backward, even though both help make function application and chaining easier to read. It also relates pipe-forward to the way collections are used and says composition is especially useful when several functions are chained together.

Reading notes

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• Pipe-forward |> passes an intermediate result to the next function, using let (|>) x f = f x.
• It shows filtering even numbers from a list as an example of applying a function to a collection result.
• Forward composition » is defined as let (») f g x = g (f x).
• The post says » is cleaner than writing the equivalent nested function calls, especially when many functions are chained.
• Pipe-backward <| applies the function on the left to the value on the right, using let (<|) f x = f x.
• The post says <| helps change operator precedence and avoid parentheses.
• Backward composition « is defined as let («) f g x = f (g x).
• It gives finding odd numbers in a list as an example of where backward composition is useful.