[jfoutz]

Uh, kinda.I think I get what you're saying, but I think you're framing it in a fairly shallow way.

I think someone good will avoid just copy and pasting the code. Shallow similarity makes it easy to thread a boolean or do something tricky with dependency injection. What I'm getting at is folks who are very capable, very fast programmers. if things aren't easy to reuse, they'll just go ahead and implement a whole new subsystem with different logs, metrics and error conditions.

I guess an example might be a type checker versus a compile time evaluator. They have a lot in common. But they're different. Adding another traversal of the AST isn't that big of a deal, really. But, there will come a time when all those passes start to be an issue, they have a lot in common. Maybe it's better to fold them all up into one or two passes.

Sometimes things are complicated. Sometimes you need to hold all that complexity in your head at once and really pick out the commonality. But that's rare. Just adding more code is a great answer for a long, long time.