Exercises in Programming Style–Declared Intentions

NOTE : read the rest of the series, or check out the source code.

If you enjoy read­ing these exer­cises then please buy Crista’s book to sup­port her work.

exercises-prog-styles-cover

Fol­low­ing on from the last post, we will look at the Declared Intentions style today.

 

Style 23 – Declared Intentions

Constraints

  • Existence of a run-time typechecker.
  • Procedures and functions declare what types of arguments they expect.
  • If callers send arguments of types that aren’t expected, the procedures/functions are not executed.

 

The problem of type checking is a solved problem in statically typed languages, so by programming in F# there’s almost nothing we need to really do for this style.

Using the same solution from the Pipeline (aka functional) style, I have added a few explicit type declarations to better comply with the constraints.

Style23_01

 

You can find the source code for this exercise here.

Enjoy what you’re reading? Subscribe to my newsletter and get more content on AWS and serverless technologies delivered straight to your inbox.


Yan Cui

I’m an AWS Serverless Hero and the author of Production-Ready Serverless. I have run production workload at scale in AWS for nearly 10 years and I have been an architect or principal engineer with a variety of industries ranging from banking, e-commerce, sports streaming to mobile gaming. I currently work as an independent consultant focused on AWS and serverless.

You can contact me via Email, Twitter and LinkedIn.

Hire me.


Check out my new course, Complete Guide to AWS Step Functions.

In this course, we’ll cover everything you need to know to use AWS Step Functions service effectively. Including basic concepts, HTTP and event triggers, activities, design patterns and best practices.

Get Your Copy