Understand monads with LINQ

This post is another attempt on explaining the M word in an approachable way. This explanation will best suite C# developers who are familiar with LINQ and query expressions. However, if you are not familiar with C# but would like to learn how powerful and expressive some of its features are, please read on!

Recap of LINQ and query expressions

LINQ is a technology introduced in C# 3.0 and .NET 3.5. One of its major applications is processing collections in an elegant, declarative way.

Here’s an example of LINQ’s select expression:

Query expressions are one of the language features which constitute LINQ. Thanks to it LINQ expressions can look in a way which resembles SQL expressions:

Before LINQ you would need to write a horrible, imperative loop which literates over the numbers array and appends the results to a new array.

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Scala’s Option monad versus null-conditional operator in C#

Today I will talk about an awesome feature of C# 6.0. We will see how it can help us understand monads in Scala!

Null-conditional operator

Imagine we have a nested data model and want to call some method on a property nested deeply inside an object graph. Let’s assume that Article does not have to have an Author, the Author does not have to have an Address and the address does not have to have a City (for example this data can be missing from our database).

This is very unsafe code since we are at risk of NullReferenceException. We have to introduce some null checks in order to avoid the exception.

Yuck! So much boilerplater code to do a very simple thing. It’s really unreadable and confusing.

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