I've been dabbling in programming language design as of late, when trying to decide if including feature 'X' makes sense or not, with readability being the main focus I realized some old wisdom:
1 line should do 1 thing - that's something C has established, and I realized that putting conceptually different things on the same line destroys readability very quickly.
For example if you write some code to check if the character is in a rectangular area, and then turn on a light when yes, you can put the bounds check expressions on the same line, and most people will be able to read the code quickly - but if you also put the resulting action there, your code readability will suffer massively - just try it with some code.
That's why ternary expressions like a = condition? expr1: expr2 kinda controversial - they're not always bad, as they can encode logic about a single thing - if said character is friendly, turn the light color should be green, otherwise red - is a good example - but doing error handling there is not.
I haven't been able to find any research that backs this up (didn't try very hard tho), but I strongly believe this to be true.
A nice thing is that some other principles, like CQRS, can be derived from this, for example CQRS dictates that a function like checkCharacterInAreaThenSetLightState() is bad, and should be split up into checkCharacterInArea() and setLightState()