== Why is this an issue?

"Cognitive complexity" is a measure of how hard the control flow of a function is to understand. Code with high cognitive complexity is hard to read, understand, test, and modify.

This rule raises on coroutines with high cognitive complexity.

As a rule of thumb, high cognitive complexity is a sign that the code should be refactored into smaller, easier-to-manage pieces.

=== Which syntax in code does impact cognitive complexity score?

Here are the core concepts:

* **Cognitive complexity is incremented each time the code breaks the normal linear reading flow.** +
This concerns, for example, loop structures, conditionals, catches, switches, jumps to labels, and conditions mixing multiple operators.
* **Each nesting level increases complexity.** +
During code reading, the deeper you go through nested layers, the harder it becomes to keep the context in mind.
* **Method calls are free** +
 A well-picked method name is a summary of multiple lines of code. 
 A reader can first explore a high-level view of what the code is performing then go deeper and deeper by looking at called functions content. +
__Note:__ This does not apply to recursive calls, those will increment cognitive score.

The method of computation is fully detailed in the pdf linked in the resources.


== Resources

* https://www.sonarsource.com/docs/CognitiveComplexity.pdf[Cognitive Complexity]