Functional Programming in C#, Second Edition

8 Functional error handling

This chapter covers

• Representing alternative outcomes with Either
• Chaining operations that may fail
• Distinguishing business validation from technical errors

Error handling is an important part of our applications. It’s also one aspect in which the functional and imperative programming styles differ starkly:

• Imperative programming uses special statements like throw and try-catch, which disrupt the normal program flow. This introduces side effects as discussed in section 3.1.1.

• Functional programming strives to minimize side effects, so throwing exceptions is generally avoided. Instead, if an operation can fail, it should return a representation of its outcome, including an indication of success or failure, as ...