Demystifying Function Sub-typing
What is a Type for a function? When can you say that a function is a sub-type of another function? Why should you even bother?
Function sub-typing is one of the most confusing areas of FP. In this talk, I'll take a deep dive and explain the core concepts of function types which applies to many different languages. More than just explaining the mere rules, I will be deriving those rules in a step-by-step fashion till the eureka moment so that you will never be confused again.
The topics covered:
- Sub-typing basics
- Covariance & Contravariance
- Function sub-typing
- Implementation gotchas in different languages (Java, Scala, Haskell, JavaScript)
Outline/Structure of the Talk
- 5 mins
- Essential basics and an invented programming language for our discussion
- What is sub-typing
- 8 mins
- Covariance & Contravariance
- Deriving the function sub-type
- 7 mins
- Usage examples for function sub-types
- Implementation caveats in popular systems
Learning Outcome
Strong understanding of function sub-typing, useful in library design and contract modelling.
Target Audience
Anyone using FP, preferably strongly typed languages like Scala, Haskell etc.
Prerequisites for Attendees
Have a good understanding of FP concepts, especially First Class Functions and types.
schedule Submitted 1 year ago
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