Actual code i have seen with my own eyes. (Not in F-35 code)
Its a way to avoid removing an unused parameter from a method. Unused parameters are disallowed, but this is fine?
I am sceptical that these coding standards make for good code!
Notably this document is from 2005. So that's after C++ was standardized but before their second bite of that particular cherry and twenty years before its author, Bjarne Stroustrup suddenly decides after years of insisting that C++ dialects are a terrible idea and will never be endorsed by the language committee, that in fact dialects (now named "profiles") are the magic ingredient to fix the festering problems with the language.
While Laurie's video is fun, I too am sceptical about the value of style guides, which is what these are. "TABS shall be avoided" or "Letters in function names shall be lowercase" isn't because somebody's aeroplane fell out of the sky - it's due to using a style Bjarne doesn't like.
I doubt I can satisfy you as to whether I'm somehow a paid evangelist, I remember I got a free meal once for contributing to the OSM project, and I bet if I dig further I can find some other occasion that, if you spin it hard enough can be justified as "payment" for my opinion that Rust is a good language. There was a nice lady giving our free cookies at the anti-racist counter-protests the other week, maybe she once met a guy who worked for an outfit which was contracted to print a Rust book? I sense you may own a corkboard and a lot of red string.
I do early returns in code I write, but ONLY because everybody seems to do it. I prefer stuff to be in predictable places: variables at the top, return at the end. Simpler? Delphi/Pascal style.
There is an element of taste. Don’t create random early returns if it doesn’t improve the code. But there are many, many cases where it makes the code much more readable and maintainable.
It might be a good guideline.
Its not a good rule because slavishly following results in harder to follow code written to adhere to it.
For example of the rule, a function might allocate, do something and then de-allocate again at the end of the block. A second exit point makes it easy to miss that de-allocation, and so introduce memory leaks that only happen sometimes. The code is harder to reason about and the bugs harder to find.
source:
> A problem with early exit is that cleanup statements might not be executed. ... Cleanup must be done at each return site, which is brittle and can easily result in bugs.
https://en.wikipedia.org/wiki/Structured_programming#Early_r...
About 90% of us will now be thinking "but that issue doesn't apply to me at all in $ModernLang. We have GC, using (x) {} blocks, try-finally, or we have deterministic finalisation, etc."
And they're correct. In most modern languages it's fine. The "no early returns" rule does not apply to Java, TypeScript, C#, Rust, Python, etc. Because these languages specifically made early return habitable.
The meta-rule is that some rules persist past the point when they were useful. Understand what a rule is for and then you can say when it applies at all. Rules without reasons make this harder. Some rules have lasted: we typically don't use goto at all any more, just structured wrappers of it such as if-else and foreach
And boiling down these guidelines to style guides is just incorrect. I've never had a 'nit: cyclomatic complexity, and uses dynamic allocation'.
Comments like yours are difficult because they’re not actionable or able to be responded to in a way you’ll find satisfying if you don’t link to the comments that you mean.
Programming language flamewars have always been lame on HN and we have no problem taking action against perpetrators when we’re alerted to them.
My memory might be lapsing here, but I don't think MISRA has such a rule. C89/C90 states that _external_ identifiers only matter up to their first 6 characters [1], while MISRA specifies uniqueness up to the first 31 characters [2].
[1] https://stackoverflow.com/questions/38035628/c-why-did-ansi-...
[2] https://stackoverflow.com/questions/19905944/why-must-the-fi...
Basically, you have code in an "if" statement, and if you return early in that if statement, you might have code that you needed to run, but didnt.
Forcing devs to only "return once" encourages the dev to think through any stateful code that may be left in an intermediate state.
In practice, at my shop, we permit early returns for trivial things at the top of a function, otherwise only one return at the bottom. That seems to be the best of both worlds for this particular rule.
I think you're talking about this "goto fail" bug?
https://teamscale.com/blog/en/news/blog/gotofail
> In practice, at my shop, we permit early returns for trivial things
Are you also writing C or similar? If so, then this rule is relevant.
In modern languages, there are language constructs to aid the cleanup on exit, such as using(resource) {} or try {} finally {} It really does depend on if these conveniences are available or not.
For the rest of us, the opposite of "no early return" is to choose early return only sometime - in cases where results in better code, e.g. shorter, less indented and unlikely to cause issues due to failure to cleanup on exit. And avoid it where it might be problematic. In other words, to taste.
> Kent Beck, Martin Fowler, and co-authors have argued in their refactoring books that nested conditionals may be harder to understand than a certain type of flatter structure using multiple exits predicated by guard clauses. Their 2009 book flatly states that "one exit point is really not a useful rule. Clarity is the key principle: If the method is clearer with one exit point, use one exit point; otherwise don’t".
https://en.wikipedia.org/wiki/Structured_programming#Early_e...
this thinking is quite different to say, 25 years earlier than that, and IMHO the programming language constructs available play a big role.
Early return is perfectly manageable in C as long as you aren't paranoid about function inlining. You just have a wrapper that does unconditional setup, passes the acquired resources to a worker, and unconditionally cleans up. Then the worker can return whenever it likes, and you don't need any gotos either.
Right, so you allow early return only in functions that do not have any setup and clean-up - where it's safe. Something like "pure" functions. And you describe a way to extract such functions from others.