Re:Assertions in Production Code? (2008)
by oftenwrong on Thursday September 06, 2018 @08:56AM
(#17925869)
If you application is interacting with the outside world, you will be dealing with side-effects, and sometimes error conditions will happen.
For example, today I am working on a service that:
- uses a database
- calls external APIs
- publishes and consumes from a message broker
- interacts with local and remote filesystems over a variety of protocols
All of these things entail error conditions, most of which throw exceptions in the corresponding libraries. Sometimes they are converted to Either/Maybe, and sometimes they are wrapped in "native" checked exceptions.
The important bits:
1. The type system and compiler make sure the programmer has to deal with the error conditions at some point. From a programmer's perspective, a checked exception bubbling up the stack is not very different from returning a monadic object up the stack.
2. The core of the application is entirely pure. No exceptions (in both senses of the word). All side effects are pushed to the boundaries.
For example, today I am working on a service that:
- uses a database
- calls external APIs
- publishes and consumes from a message broker
- interacts with local and remote filesystems over a variety of protocols
All of these things entail error conditions, most of which throw exceptions in the corresponding libraries. Sometimes they are converted to Either/Maybe, and sometimes they are wrapped in "native" checked exceptions.
The important bits:
1. The type system and compiler make sure the programmer has to deal with the error conditions at some point. From a programmer's perspective, a checked exception bubbling up the stack is not very different from returning a monadic object up the stack.
2. The core of the application is entirely pure. No exceptions (in both senses of the word). All side effects are pushed to the boundaries.