Examples are the best documentation

Right, one of the best out-of-box tooling decisions for Rust is that by default, and out of the box cargo will assume all your documentation examples are tests it should compile and execute.

This means so long as you run the tests before shipping you basically can't ship with examples you forgot to update after an API change because they either don't compile or don't work.

And you might think well, nobody would ship examples that don't even compile right? But on more than one occasions I've used a Microsoft C# library that comes with examples clearly hand made by their engineers (yes I'm that old that it couldn't be LLM output) without checking they work. Somebody has sketched out what ought to work, they haven't tested it, and a reviewer has seen that it looks right and OK'd it, but again, never tested that it works. This is extremely frustrating because the documentation is wrong but now what?

Took the words right outta my mouth!

Of course we want a full list of public functions with all the info. But with just a list of functions it's often still not quite clear how you're supposed to setup and call them, unless you dig through the whole list and try to understand how they interact internally. A few short examples on "How do I init the library/framework so I can start using it", "How do I recover from a failure case", etc. makes the docs infinitely more accessible and useful!

I've developed the habit of checking the end of the page, because that's where the examples are, when there are any.

In terms of actually documenting something, examples are not documentation at all -- they are merely illustration. The annotations accompanying the examples (if any) are better documentation than the examples themselves.

Like a lot of advice for documentation, it's not completely accurate. Good documentation should cover 3 "kinds" of users.

* Absolute beginners/newbies: These users are best helped by showing a "happy path" through the tools, with plenty of examples to show you why things are that way, so they build up an understanding of how things are supposed to work.

* Regular users: These are best helped by a "topic" oriented style of documentation. Topics can take one element of a tool and go really in-depth on it. For example, a HTTP request library might have a topic page entirely dedicated to session authentication, explaining how to persist headers and cookies between requests in the library and what a session object does.

* Power-users/developers: These users are served by reference docs the most. Just a big index of classes, functions and argument doc strings that refer to each other is enough here, because anyone reaching for reference docs is usually doing it because they have a very specific issue.

As for real world examples I'm familiar with; NodeJS libraries often only have beginner docs, and the moment you go off of that happy path it becomes very difficult to reason about what you're doing (not helped by a lot of frameworks preferring you use CLI tools to build up your code, maybe this has changed), the python ecosystem often has good topical docs at the cost of poor reference documentation and C libraries very often only ship with reference documentation.

Programming-wise, it's easy to make reference docs (since they can be derived from comments in the source code) and beginner docs (because you probably have a mental model on how someone is meant to start using something), while writing good topical documentation is an entire skill on its own (since it requires understanding where someone might struggle with something.)

The best documented tools usually have all three covered at the same time, while poorly documented tools usually only have beginner or reference documentation. Only having beginner docs makes it impossible for someone to really learn a tool ("draw the rest of the fucking owl"). Only having topical docs makes it hard to figure out where to start. Only having reference docs is hard to reason about because there's nothing explaining to you how the references are meant to fit together.