F# – Referential equality for tuples, discriminated unions and records

Yan Cui

I help clients go faster for less using serverless technologies.

By default, tuples, discriminated unions and records have what is known as structural equality – i.e. if two instances of these types have the same set of values then they are considered equal, just like value types – despite being reference types:

Tuples

image

Discriminated Unions

image

Records

image

To facilitate this form of equality, the F# compiler automatically overrides Object.Equals and Object.GetHashCode methods for you. However, there may be times when you want to use referential equality with these types, in which case you just need to add the ReferenceEquality attribute to your type:

image


 

Whenever you’re ready, here are 4 ways I can help you:

  1. If you want a one-stop shop to help you quickly level up your serverless skills, you should check out my Production-Ready Serverless workshop. Over 20 AWS Heroes & Community Builders have passed through this workshop, plus 1000+ students from the likes of AWS, LEGO, Booking, HBO and Siemens.
  2. If you want to learn how to test serverless applications without all the pain and hassle, you should check out my latest course, Testing Serverless Architectures.
  3. If you’re a manager or founder and want to help your team move faster and build better software, then check out my consulting services.
  4. If you just want to hang out, talk serverless, or ask for help, then you should join my FREE Community.

 


1 thought on “F# – Referential equality for tuples, discriminated unions and records”

  1. Pingback: Contrasting F# and Elm’s record types | theburningmonk.com

Leave a Comment

Your email address will not be published. Required fields are marked *