I hate this convention to put literals on the left hand side of the comparison. Every time I stumble upon code like this my brains stalls for an instant trying to make sense of the expression. It just looks ugly and wrong in my opinion.
It's also mostly useless because your compiler should warn you about your first construct (and tell you to add a layer of parens if that's what you really want to do).
I realize I'm being a bit irrational with this whole thing but for some reason code like this drives me nuts (that and people not putting space around arithmetical operators and such: int a=2*4+foo(1,2,3)).
I do a ton of code reviews, often as part of an interview process, less often, for embedded developers. Conditionals written with literal lvalues is something of which I tend to take note. You're right, it's not natural, and it's less readable, but there's usually a reason why people do it: experience. If you often work in weakly typed languages, or those which allow for weird coercion in conditional statements, it's sadly often easier to form a habit which guarantees fewer bugs than it is to say "I'll always type the boolean equality/strict equality operator."
"But why don't you use better languages, then?" Because in many cases (low-level resource-constrained systems programming), it's much, much easier to deal with these weird gotchas than to attempt to get exotic  languages such as Python, Ruby, Java, and sometimes even C++ (heap? who needs a heap??), to work. Even in cases where you're able to get these languages to work easily, you're just forcing yourself to become intimately familiar with the internals of some language with which you'll ultimately wind up wrestling . Normally the point of such languages is to abstract away the system. This is the exact opposite of what you need in these environments.
"But it annoys me when people use literal lvalues where they don't need to." Ah, but this is the rub of forming a habit.
1: I'm mostly sarcastic in my use of the word "exotic" here. Don't go crazy, now. ;-)
2: Though to totally contradict myself, I will say that both Rust and Go look very, very interesting here.
There is nothing incorrect or dubious in C about an expression like if (foo = bar), so it wasn't considered a reason to warn the user about for a long time, despite being a rather common culprit for bugs. Compilers popping up warnings about that is a fairly recent event.
I like doing it in certain cases. It definitely helps in a while loop when you are working with a stream, iterator, or stack and pulling items off while it isn't empty. Not really sure about the if, it's just kind of convenient sometimes. Guess it all comes down to preference. Too much use and it becomes very unreadable.
With that if statement, does it first assign the value of db.getNextResult() and then check the elt.shouldProcess variable to see if it is true or false, or does it firstly check to see if elt.shouldProcess is true or false and then load the next result from the database?
According to C99, 6.5.16 clause 4, the order of evaluations on operands is undefined and if an attempt is made to modify or access the operand is after the next sequence point then the behavior is undefined.
Chris, && and || are short-circuited operators that create sequence points. They are exceptions to that rule.
except where noted [e.g. special rules for && and ||], the order of evaluation of operands of individual operators and subexpressions of individual expressions, and the order in which side effects take place, is Unspecified.
This is basic stuff Chris, let's not debate the obvious, this kind of code is all over the place in the Linux kernel.
Also, where is the place in the C99 standard that details the exception? Genuinely curious. When I reviewed the standard, all that is said about the if statement is in section 184.108.40.206, and that says nothing about short circuited logic, certainly nothing about "exceptions to the rule". This seems compiler specific, but I'm happy to be shown to be wrong - if you can point me to the part in the standard.
GCC isn't the only compiler on the planet :-). Other compilers either started doing it more recently, or not at all. The construct it most often warns about is fairly idiomatic on Unix platforms, but not everywhere, so a lot of vendors were not quite as bothered about it.
GCC is indeed not the only compiler around, which is why I said "at least" :-) Even if you're stuck with some other compiler for production builds, it's handy to be compiling regularly with a variety of compilers so as to benefit from the union of the diagnostic abilities of all of them.
The construct is a useful idiom, but oftentimes there would be or ought to be a local coding standard recommending that you make what you're doing explicit by comparing the assignment result to the appropriate flavour of zero:
if ((foo = bar) != NULL)
Now everybody can see what's going on, the warning doesn't arise, and no pedants can complain about the theoretically-unnecesary parentheses in `if ((foo = bar))`.
> GCC is indeed not the only compiler around, which is why I said "at least" :-) Even if you're stuck with some other compiler for production builds, it's handy to be compiling regularly with a variety of compilers so as to benefit from the union of the diagnostic abilities of all of them.
In my case, at least one of the compilers in question was for the 8051, the platform that won't fucking die. Due to the peculiarities of the aforementioned piece of silicon crap, the compiler was not entirely ANSI-compliant (various #pragmas were actually required to produce working code, indicating various parameters related to memory organisation and the such), thus making it rather difficult to compile the codebase with anything but that particular compiler.
> The construct is a useful idiom, but oftentimes there would be or ought to be a local coding standard recommending that you make what you're doing explicit by comparing the assignment result to the appropriate flavour of zero
I've written both my greatest (and most ingenious) code, and my absolute worst code while drunk. It seems to send me to one or the other extreme. No "average" drunk code here! Just awesome problem solving, or terrible terrible bugs!
Why is this hatred and stereotyping in the comments of a front page Hacker News article?
Is it particularly uncommon for someone that both drinks and is passionate about programming to write code drunk? Someone incorporated an arduino breathalyzer into a source control tool with some jokey features.
What's so stupid or frathouse-ish about that? It's not super-duper strait laced and serious, but neither is life.
If you want to get drunk and write code that's great. Good for you. But for a bunch of HN users to vote that up to the front page and be super excited about it is dumb. It's the acceptance and promotion of immature "brogrammer" culture that I find really distasteful.
So you're dismissing a project because you drew an association between it and a boogieman caricature of people that you (perhaps even rightly so) don't like? OK, be my guest, but keep in mind that's a dangerous road to head down.
It boggles my mind that this needs to be said, even if in jest. Just looking at the subject, I think, "What kind of idiot needs to be told not to commit when drunk? Do they need to be told not to drive when drunk too?" And the article is worse than the subject.
And it goes beyond being drunk: sometimes I code when I'm tired but can't sleep. I have a vcs to ensure I don't trash something irretrievably; also tests and ideally a decent type system to increase the chances my code does what it should.
What about a check for prescription pain killers or amphetamines? Oh wait, those are culturally acceptable mind altering things. I'm half joking but this is a neat hack, although I know many functioning alcoholics that would laugh at the concept of this.
One of my old colleagues had the bright idea to log onto one of our production systems to "re-index some of the database tables" after coming home one Easter eve.
And yes, he wasn't directly sober at the time.
I was moderately amused when I got woken up about 3 AM and got to spend a few hours trying to revert the "re-indexing" ...
I think integration with ssh-key management to prevent people logging onto production systems when drunk would be a good idea for this project, don't be surprised if there is a pull request from me in the future ...
I'm pretty sure it's common to install a breathalyzer in cars nowadays if you've been caught with driving under the influence (probably repeatedly or over a certain percentage) in various countries / states.