Not sure the concept applies cleanly here. Affordance is about perceiving possibilities from an interface or environment.

For the subject of programming language idioms, the main factors are restrictions or patterns the language offers, and how naturally they fit within their context, not just perception by the user.

I’m curious, how do you make the distinction that restrictions/patterns/context are not just as much perveived properties of the interface to the device you are programming?

Are you perhaps perceiving perception as just visual perception? (See what I did there? :)