Not if you are encapsulating and naming effectively...
Why read 100 lines when you can read 20 and find concerns in one routine you are concerned with?
Function calls can be expensive. However, optimization can come whenever you need it, and if what you need is one call vs 5, it is trivial to move that code back into a single routine.
Rarely does having more functions solve “does this do what I expect.”
With a full-featured language specific IDE, it is very easy to navigate through even complicated spaghetti. It makes debugging call traces simple, with a GUI.
However, many other file viewers and editors make this much more complicated, and it can be frustrating to follow code that is making heavy use of modularization.
If you are grepping your way through a deeply modular code base it can quickly become difficult to keep track of anything.
If you need a fancy IDE to navigate around code in order to understand it, that might be crappy or poorly organized code.
Not a dig at nice IDEs, just code that requires one to navigate and understand.
> Not a dig at nice IDEs, just code that requires one to navigate and understand
A nice IDE helps you reason about code, no matter what the underlying architecture is. That is why there is a market for them.
No, and this is one of the reasons inheritance has lost popularity. Splitting some functionality across many files adds significantly to the cognitive load of figuring out what code is actually even running. After you trace that information out, you need to keep it all straight in your head while debugging whatever you’re working on. That’s even more problematic when you’re debugging, which implies you already don’t really understand what the program is doing.
And that’s in the case where things are named well. When they’re inevitably accidentally named in confusing or incorrect ways that can contribute to the bug itself and cause the code to be even more confusing.
Extreme levels of encapsulation has its own issues when, actually, the original author is wrong and you really do need some public access to some member. No one writing code is clairvoyant, so excessive encapsulation is common.
This is the crux, if your goal is to figure out what code is running, if you can keep the program in your head, if you have small simple programs splitting things up is harmful.
But there is this murky line, different for everyone, and even different for the same person from day to day, where even with the best intent, no matter how good you are, you can't keep the program in your head.
At that point, you need to give up the idea that you can. Then you change perspective and see things in chunks, split up, divide and conquer, treat portions as black boxes. Trust the documentation's, pre and post conditions. Debugging becomes verifying those inputs and returns; only diving into the code of that next level when those expectations are violated.
It depends on the change. It depends on the code organizational structures. It depends on the consistency of the code. It depends on the testing setup. It depends on the experience of the person changing it. It depends on the sensitivity of the functionality. It depends on the team structures.
Separating the code of your SQL server, HTTP server, Crypto Library, Framework, Standard Library, from your CRUD code is perfectly fine, and people understand this concept well, and even the most fervent anti-Clean-Code person won't complain about this separation existing.
But there is a good reason we separate those things from our CRUD codebase: it's because they can function separately fine, they're reusable, they're easy to isolate/reproduce problems, and they're at a totally different abstraction level.
The problem is separating code from the same level of abstraction, such as breaking a business logic class into many for mainly aesthetic reasons, such as method/class/module length, or to avoid having comments in the code (again as recommended by Clean Code), things that people are mentioning here in this thread.
EDIT: As someone said above, "20 files with 20 functions each does not cause high cognitive load, if the scope of each file and each function makes sense". In the end it's not the length or the number of methods/classes that matter, but how well separated they are. Having hard rules does not automatically make for good code, and it's often quite the opposite.
However, Can you?
You are using black box code from a web server, a sql database, the operating system, crypto libraries, and a ton more; You don't dive into that source code except in extraordinary circumstances, if you even can. In a large program, you end up treating code owned by you or your company as the same way.
In this scenario you are still making large meaningful changes by focusing on the level of abstraction you are at.
Encapsulation is hard and a lot of what people call encapsulation isn’t. For example, taking a global variable and moving it to a class is not encapsulation. You have to actually do the hard work of removing the dependency on global shared state. Just changing everything to mutate the new global through an accessor to a “god” object that gets passed everywhere is accomplishing nothing at all. Worse than nothing, you’re complexifying without fixing the root problem: global mutable state.
A cleverly-named way of disguising global mutable state does not make it better.
When you only have to superficially skim the code, that works.
If there are incorrect abstractions, such as logging, transaction logic or manual error handling mixed with "well named function calls", then it is already very problematic even to skim.
If you have to debug, it quickly becomes torture. Especially if state is involved and shared between multiple methods or classes.
If you have to reimplement the code: you're probably fucked.