Functional error handling – parsing command line arguments in F#

In this post, which is the second part of the series Functional error handling in F# and C#, we will examine an application for parsing command line arguments with error handling.

The functional approach uses Applicative Functors. Applicative Functors and the basics of functional error handling, only with immutable objects and without the use of exceptions, are explained int the first post of this series: Error handling with Applicative Functors in F# and C#.

A complete solution with all the code samples from this series can be found here.

As a starting point I took this F# console application template and reimplemented it with railway oriented error handling in F# and C#. The original version writes error messages directly to the console, which is totally ok in many situations. However, the railway oriented approach offers a bit more flexibility and safety because it will let the caller decide on how to handle the failure cases.

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