Simplicity Principle: Through the Prism

Clarity #

The ability to hold the model or behavior of a module in your mind - being able to reason about about it without having to rely on detailed instructions.

A good indicator: can you explain it to a layperson?

This can be achieved through good abstractions:

• Few elements (less than 7, ideally less than 5), observing Miller’s Law or the rule of 3
• Describe behaviors and intentions.
• Be mindful of leaky abstractions.

Modularity #

A system is created a composition of modules, that are as independent as self contained as they can be.

A good indicator: how easy is it to remove the feature completely from the system? How many places do you need to change to remove it?

Parsimony #

Focus on what is relevant:

• Be intentional.
• Avoid superfluous or assumed functions.
• Provide guarantees over assertion.
• Remove that which is no longer relevant.

To paraphrase Albert Einstein, a parsimonious system is “As simple as it can be, but not simpler than that”.

Code is a liability - don’t take on more than you need to carry.

Keep it simple (but not simplistic).